Removelibiconv from gitlab - it is not needed.
Ensure .ssh key directory is created with the correct permissions.
The norokiri setup changed (how did this ever work?) - fix it.
Install gitlab-shell into the current sytem when gitlab is enabled.

This is required because gitlab's push depends on a .ssh/authorized_keys shell
override which needs to be a hardcoded-path.

If we use the nix path and ever update the gitlab-shell binary then all
existing authorized_keys entries will become invalid, or worse, call an old
gitlab-shell with a potential security bug.