Remove fine-grained repository housekeeping RPCs

Closes #4039

See merge request https://gitlab.com/gitlab-org/gitaly/-/merge_requests/5654



Merged-by: Patrick Steinhardt <psteinhardt@gitlab.com>
Approved-by: karthik nayak <knayak@gitlab.com>
Approved-by: Justin Tobler <jtobler@gitlab.com>
Reviewed-by: karthik nayak <knayak@gitlab.com>