Tutorial groups: Change channel prefix for tutorial-groups

[lennart-keller]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• This is a small issue that I tested locally and was confirmed by another developer on a test server.
• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Server

• Important: I implemented the changes with a very good performance and prevented too many (unnecessary) database calls.
• I followed the coding and design guidelines.
• I modified multiple integration tests (Spring) related to the features (with a high test coverage).

Motivation and Context

Automatically generated channels for lecture, exercises and exam have a certain prefix (lecture-, exercise-, exam-). This PR introduces such a prefix for tutorial-group channels.

Description

The automatically generated channel name for tutorial groups is prefixed with tutorgroup-, instead of $. Additionally, the maximum allowed length for the name got increased to 30, which is the same length as for other channels.

Steps for Testing

Prerequisites:

• 1 Instructor
• 1 Course

1. Create or edit the global tutorial group configuration of the course: Make sure that "Use Artemis managed Tutorial Group Channels" is enabled
2. Create a tutorial group
3. A channel should be created in the form of tutorgroup-title-of-tutorgroup

Review Progress

Performance Review

• I (as a reviewer) confirm that the client changes (in particular related to REST calls and UI responsiveness) are implemented with a very good performance
• I (as a reviewer) confirm that the server changes (in particular related to database calls) are implemented with a very good performance

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Test Coverage

Screenshots

[DominikRemo]

LGTM

[basak-akan]

Code looks good 👍 I have just a small comment.

[reschandreas]

Tested locally, works code also lgtm

[basak-akan]

Thank you for addressing my comment. Code looks good 👍

[laurenzfb]

Demonstrated in testing session, code LGTM as well

[rstief]

Tested in Testing Session.

[JohannesStoehr]

Changes and code look good to me.
But we should definitely unite all these occurrences of 30 and other numbers into some constants in the future!

[florian-glombik]

Tested on ts1, and the code looks fine, as the magic numbers seem to be present at multiple places right now and should probably be replaced within one dedicated PR

[reschandreas]

reapprove