[TASK] Add github contribution, funding and action configurartions

Relates: #86

.github/CONTRIBUTING.md

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+# Contributing
+
+When contributing to this repository, please first discuss the change you wish to make via issue,
+email, or any other method with the owners of this repository before making a change.
+
+## Getting Started
+
+* Make sure you have a [GitHub account](https://github.com/signup/free)
+* Submit a ticket for your [issue](https://github.com/extcode/cart/issues), assuming one does not already exist.
+  * Clearly describe the issue including steps to reproduce when it is a bug.
+* Fork the repository on GitHub
+
+## Making Changes
+
+* Create a topic branch from where you want to base your work.
+  * This is usually the master branch.
+  * Only target release branches if you are certain your fix must be on that
+    branch.
+  * To quickly create a topic branch based on master; `git checkout -b
+    fix/master/my_contribution master`. Please avoid working directly on the
+    `master` branch.
+* Make commits of logical units.
+* Use `./php-cs-fixer fix --config-file Build/.php_cs` to make sure the code is formatted correctly.
+* Make sure your commit messages are in the proper format. Use either `[TASK]`, `[FEATURE]`, `[BUGFIX]` or `[DOC]`
+
+````
+    [TASK] Make the example in CONTRIBUTING imperative and concrete
+
+    The first line is a real life imperative statement.
+    The body describes the behavior without the patch,
+    why this is a problem, and how the patch fixes the problem when applied.
+
+    Resolves: #123
+````
+
+* Make sure you have added the necessary tests for your changes.
+* Run _all_ the tests to assure nothing else was accidentally broken. However travis will do that for you as well.
+
+## Making Trivial Changes
+
+For changes of a trivial nature, it is not always necessary to create a new issue.
+
+## Additional resources
+
+* [Rendered documentation](https://docs.typo3.org/typo3cms/extensions/cart/)
+* [How to Write a Git Commit Message](http://chris.beams.io/posts/git-commit/)
+
+
+## Contributor Code of Conduct
+
+As contributors and maintainers of this project, and in the interest of fostering an open and
+welcoming community, we pledge to respect all people who contribute through reporting issues,
+posting feature requests, updating documentation, submitting pull requests or patches, and other
+activities.
+
+We are committed to making participation in this project a harassment-free experience for everyone,
+regardless of level of experience, gender, gender identity and expression, sexual orientation,
+disability, personal appearance, body size, race, ethnicity, age, religion, or nationality.
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery
+* Personal attacks
+* Trolling or insulting/derogatory comments
+* Public or private harassment
+* Publishing other's private information, such as physical or electronic addresses, without explicit
+  permission
+* Other unethical or unprofessional conduct.
+
+Project maintainers have the right and responsibility to remove, edit, or reject comments, commits,
+code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct. By
+adopting this Code of Conduct, project maintainers commit themselves to fairly and consistently
+applying these principles to every aspect of managing this project. Project maintainers who do not
+follow or enforce the Code of Conduct may be permanently removed from the project team.
+
+This code of conduct applies both within project spaces and in public spaces when an individual is representing the project or its community.
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by opening an issue or contacting one or more of the project maintainers.
+
+This Code of Conduct is adapted from the [Contributor Covenant](http://contributor-covenant.org),
+version 1.2.0, available at [http://contributor-covenant.org/version/1/2/0/](http://contributor-covenant.org/version/1/2/0/)

.github/FUNDING.yml

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+github: extcode
+custom: ["https://paypal.me/extcart"]

.github/ISSUE_TEMPLATE.md

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+<!---
+Thanks for filing an issue 😄! Before you submit, please read the following:
+
+Check the other issue templates if you are trying to submit a bug report, feature request, or question
+Search open/closed issues before submitting since someone might have asked the same thing before!
+-->

.github/ISSUE_TEMPLATE/Bug_report.md

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+---
+name: Bug Report
+about: If something isn't working as expected.
+
+---
+
+## Bug Report
+
+**Current Behavior**
+A clear and concise description of the behavior.
+
+**Expected behavior/output**
+A clear and concise description of what you expected to happen.
+
+**Environment**
+- TYPO3 version(s): [e.g. 8.7.12, 9.3.0]
+- cart version: [e.g. 7.0.5]
+- Is your TYPO3 installation set up with Composer (Composer Mode): [yes, no]
+- OS: [e.g. OSX 10.13.4, Windows 10]
+
+**Possible Solution**
+<!--- Only if you have suggestions on a fix for the bug. -->
+
+**Additional context**
+Add any other context about the problem here.

.github/ISSUE_TEMPLATE/Feature_request.md

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+---
+name: Feature Request
+about: I have a suggestion!
+
+---
+
+## Feature Request
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I have an issue when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen. Add any considered drawbacks.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Teachability, Documentation, Adoption, Migration Strategy**
+If you can, explain how users will be able to use this and possibly amend the documentation.

.github/ISSUE_TEMPLATE/Support_question.md

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+---
+name: Support Question
+about: If you have a question, please check out our [Slack Channel](https://typo3.slack.com/messages/ext-cart/)!
+
+---

.github/workflows/ci.yaml

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+name: CI
+on:
+  - pull_request
+jobs:
+  check-composer:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Validate composer.json
+        run: composer validate
+
+  php-linting:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-version:
+          - 8.1
+          - 8.2
+          - 8.3
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "${{ matrix.php-version }}"
+          tools: composer:v2
+
+      - name: PHP lint
+        run: "find *.php Classes Configuration Tests -name '*.php' -print0 | xargs -0 -n 1 -P 4 php -l"
+
+  coding-guideline:
+    runs-on: ubuntu-latest
+    needs:
+      - php-linting
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "8.1"
+          tools: composer:v2
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress --no-suggest
+
+      - name: Coding Guideline
+        run: vendor/bin/php-cs-fixer fix --config=Build/.php-cs-fixer.dist.php -v --dry-run --using-cache=no --path-mode=intersection ./
+
+  code-quality:
+    runs-on: ubuntu-latest
+    needs:
+      - php-linting
+    strategy:
+      matrix:
+        include:
+          - php-version: '8.1'
+            typo3-version: '^12.4'
+          - php-version: '8.2'
+            typo3-version: '^12.4'
+          - php-version: '8.3'
+            typo3-version: '^12.4'
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "${{ matrix.php-version }}"
+          tools: composer:v2
+
+      - name: Install dependencies with expected TYPO3 version
+        run: |-
+          composer require --no-interaction --prefer-dist --no-progress "typo3/cms-core:${{ matrix.typo3-version }}" "typo3/cms-extbase:${{ matrix.typo3-version }}" "typo3/cms-frontend:${{ matrix.typo3-version }}"
+
+      - name: Code Quality (by PHPStan)
+        run: vendor/bin/phpstan analyse -c Build/phpstan.neon
+
+  tests-acceptance:
+    runs-on: ubuntu-latest
+    needs:
+      - coding-guideline
+      - code-quality
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: cachix/install-nix-action@v17
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+
+      - name: Run Unit Tests PHP8.1
+        run: nix-shell --arg phpVersion \"php81\" --pure --run project-test-unit
+
+      - name: Run Unit Tests PHP8.2
+        run: nix-shell --arg phpVersion \"php82\" --pure --run project-test-unit
+
+      - name: Run Unit Tests PHP8.3
+        run: nix-shell --arg phpVersion \"php83\" --pure --run project-test-unit