Publish event according to project repo replication version

What does this MR do and why?

This change partially introduces a new version (V2) of project repository replication for GitLab's Geo feature.

The main improvement is adding a feature flag that allows switching between two different approaches for handling repository replication events. In the old version (V1), events are created for Project objects, while the new version (V2) creates events for ProjectRepository objects instead.

The code adds logic to check which version is enabled and only publish replication events for the appropriate object type based on the version. A new feature flag called "geo_project_repository_replication_v2" is introduced but disabled by default.

Further changes to make this replication version work are being worked on through Geo: Improve verification and replication handl... (&17974)

References

Geo: Handle toggling between legacy and v2 of p... (#563394)

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