LocalVC: Support multiple branches

[b-fein]

Is your feature request related to a problem?

As part of the software engineering lecture, we conduct exercises where multiple branches are required and checked by custom tests in our build pipeline.

Example:

• teaching the basic Git workflow with branches, merging, and tagging
• iterative refactoring

It might also be useful for team exercises with multiple students working on a task to have multiple branches.

Describe the solution you'd like

GitLab currently allows students to push to any branch. LocalVC restricts this to main as far as I know. It would be nice if the push would be allowed for other branches as well.

Open questions:

• Configuration as instance-wide setting, or per exercise?
  • instance-wide: easy to configure in a central location, but some exercises might not want this
  • per exercise: already many options for programming exercises, would add an additional one here
• Displaying other branches in the commit history/changelog built into Artemis
  • would not be required by us, I guess checking out the repo and looking at it there should be fine

Describe alternatives you've considered

No response

Additional context

This would be a blocker for us to migrate from GitLab to LocalVC.

[krusche]

We explicitly forbid pushing to other branches, because for simple exercises, students are confused if they (accidentally) do that and they do not get any results. Also, branches can easily lead to merge conflicts for inexperienced students.

Therefore, I would suggest to add this option on the exercise level.

In Gitlab and Bitbucket, this was also configured on the "exercise level"