* Create systemd socket override for systemd-journal-gatewayd
As stated in https://github.com/home-assistant/supervised-installer/issues/247 the default action for systemd-journal-gatewayd is to listen on HTTP port while Supervisor needs Unix socket file that's bind mounted in Docker container. This override changes socket location.
* Check and fix systemd socket file
As stated in #247 with the default setup the path /run/systemd-journal-gatewayd.sock may be a directory, not a file, we have to fix that
* Remove unnecessary unit file
Socket location change has been moved to systemd override which is the suggested way of changing original packaged unit behavior
* Rename hassio-supervisor.conf to 10-hassio-supervisor.conf
