Implement change of storage for Mercurial projects
Heptapod still supports having only one Mercurial-enabled repository storage (i.e Gitaly and HGitaly services). However, it will be in the not-so-far future.
At this point, Projects::UpdateRepositoryStorageService
will have to support Mercurial projects, its point being to move repositories from one storage to the other. The already are some provisions toward that, but it's obviously incomplete (see in particular how Concerns::updateRepositoryStorageMethods
handles the Project repository).