This changes the repository type from a binary `wiki?` to a type. So
we can have more than 2 repository types.
Now everywhere we called `.wiki?` and expected a boolean, we check
that type.
This used to be executed because of the post receive worker, but this
uses Gitlab::GlRepository.parse now. So this removes dead code and
reduces the number of calls on `#legacy_storage_path`.
This new param allows us to share project information between components
that don't share or don't have access to the same filesystem
mountpoints, for example between Gitaly and Rails or between Rails and
Gitlab-Shell hooks. The previous parameters are still supported, but if
found, gl_repository is prefered. The old parameters should be deprecated
once all components support the new format.
