Update Unturned Egg to use Dedicated Server, Supersedes #248
This is a new unturned egg that uses a generic image to run the server. It still uses the rocketmod files for the workable console but also doesn't need mono to run.
Uses dedicated Unturned server in 64-bit mode in egg and install script
Moving the egg to GitLab from Docker Hub because the builds are much faster and it's more integrated with the project.
Removed `alpha_num` requirement on username
This is gonna be a fun one.