Backport #8901 - Adjusted slightly for 1.9
In investigating #7947 it has become clear that the storage component of go-git repositories needs closing.
This PR adds this Close function and adds the Close functions as necessary.
In TransferOwnership the ctx.Repo.GitRepo is closed if it is open to help prevent the risk of multiple open files.
Fixes#7947
* Add Activity page to repository
* Add request data for activity
* Add issue data for activity
* Add user unit right checks
* Add releases to activity
* Log repository unit loading error