Enhance revert feature in Web UI to support forks

Description

The revert functionality in GitLab's Web UI currently only allows creating revert commits directly within the target project. This setup can be limiting for users who need to work within forks due to project permissions or workflow preferences.

Suggested Improvement

The proposal is to enhance the revert functionality by enabling revert operations within a user's fork of the project. This would allow users to manage revert changes in their forks and then propose these changes to the target project via merge requests.

Potential Implementation Details

A practical approach to implementing this feature could involve adding a dropdown menu in the revert dialogue, similar to the one used for selecting the source branch for merge requests. This dropdown would allow users to choose where the revert commit should be created—either in the target project (as is currently the case) or in their fork. If the user selects their fork, the revert commit would be created there, and GitLab would automatically set up a merge request to the original project from this revert branch. This feature would make the revert process more flexible and user-friendly, particularly for contributors who prefer or need to work within forks.