WIP: Git CLI auth using OpenIDConnect tokens.

What does this MR do?

Allow the user to use Bearer Token obtained from the OpenID Connect provider as password for Git over http.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

When using an OpenID Connect provider to control the authentication to the Gitlab UI, it should be possible to make use of the same OP to provide the authentication for the Git commands over HTTP.

The configuration for the OIDC provider can map scopes from the JWT to Gitlab authz Access Tokens scopes to ensure the same granularity and control as in the case of using Personal Access Tokens.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Depends on #57365 (closed) and #57352 (closed)