Bulk project repository storage move API

Project repository storage moves API is great for moving projects one by one to new storage shards. We need a way to move all repos off a current storage shard.

Proposal

Add API endpoint to move all projects off given storage shard.

POST /project_repository_storage_moves

{
  "source_storage_name":"storage1",
  "destination_storage_name":"storage2",
}

destination_storage_name is optional

A nice to have/potential follow on would be to select a percentage or number of projects you want to move from source_storage_name rather than moving all from source_storage_name. I could see folks wanting some other filter criteria too like all projects in a specific group.