👷 ci: add skaffold build ci action

[W3D3]

This PR adds two new GitHub actions:

• One action that is run on every PR that simply builds all the images as a very weak form of catching errors that break the whole application
• One action that is run on pushing to a release branch, that builds and pushes the images to GHCR
  • Images are tagged with {version} based on the branch name release/{version}.

[ammerzon]

Thank you for adding these workflows, so we finally have the images on GHCR 😁

[ammerzon]

Approved. One general question regarding the commits. Do we have a convention on whether the commit message after the component type should start with an upper case or lower case letter?

[W3D3]

Approved. One general question regarding the commits. Do we have a convention on whether the commit message after the component type should start with an upper case or lower case letter?

The commitlint action currently doesn't check, but I don't have any strong feelings on how it should be.

[ammerzon]

Same. We could use the format with the uppercase letter because most of the older commits are written this way.

[W3D3]

Same. We could use the format with the uppercase letter because most of the older commits are written this way.

We'll just have to extend the commitlint.config.js with a rule that forces sentence case for the body then.
See: https://github.com/conventional-changelog/commitlint/blob/master/docs/reference-rules.md#body-case