[Platform] Create REST endpoints + controller for managing xCluster async replication relationships

[atarw]

Create REST API endpoints + a controller to expose the xCluster replication management that was implemented earlier in #9123 and #9122.

PUT /api/v1/create_xcluster_replication

DELETE /api/v1/delete_xcluster_replication

PUT /api/v1/pause_xcluster_replication

PUT /api/v1/resume_xcluster_replication

POST /api/v1/sync_config_with_platform

Also update v1.routes to map the new endpoints to the controller