lsio-unifi-controller-preinstalled

AS OF ls180, this is now redundant because lsio is now installing the deb file now.

Modified version of linuxserver.io's unifi-controller image.

Modifications:

1. Pre-installed deb package to avoid needing to install it at container runtime.
2. Modified /etc/cont-init.d/20-config to by more selective about what it chown's, because you don't really need to chown the entire directory full of lib jar files.

Using renovatebot, github actions and github packages, this should automatically track the upstream linuxserver images for the forseeable future.

See https://github.com/linuxserver/docker-unifi-controller for usage instructions.