Even though there is a dialog users must accept when removing a
repository & directory being removed is shown, it's possible users
assume this only removes files which are part of the repository after
pointing the custom-directory to their home directory or similar.
Removing repositories which point to a custom-directory now only
remove packages and server meta-data to prevent accidents.
Resolves#119481.
Campbell Barton
Hans Goudey
Bastien Montagne