Apply SELinux context correctly to Workhorse files

- Run SELinux helper after helper files associated with GitLab Workhorse
  are created and able to receive file context restoration commands
- Move GitLab Workhorse UNIX sockets into a directory allowing them to
  inherit the correct SELinux file context after a service restart
- Adds GitLab Workhorse Helper class to ensure new UNIX sockets always
  inherit the proper SELinux file context
- Add rspect tests for new GitLab Workhorse helper
- Add clause to remove orphan GitLab Workhorse sockets if they exist
- Add rspec test to ensure orphan socket cleanup happens when necessary

Closes https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/5694



Signed-off-by: Robert Marshall <rmarshall@gitlab.com>