Group Level Wiki: BE Add the git routes to allow repository pushes from ssh and http

Problem to solve

Group wiki repositories need to be able to receive Git pushes over HTTP and SSH.

Note: This issue is a child of the Group Level Wiki Implementation Epic &2214 (closed)

Proposal

Continue the work in #207865 (closed) to implement support for Git pushes.

Tentative MR Breakdown

Only one MR is predicted for now.

Permissions and Security

Use the permissions established in #207872 (closed).

Documentation (remove if not applicable)

This issue does not require the creation of documentation.

Testing

Testing Approach

• Analyze the existing project wiki specific tests. Is it covered at the appropriate level?
• Adapt existing tests for project wikis to group wikis.

Success Criteria

• Group wiki repositories can be pushed over HTTP
• Group wiki repositories can be pushed over SSH

Links / references