Add docker container for server instance

[Exiled1]

We should add a docker file that sets up a Cimvr server instance. This would allow us to have easy server deployment.

[Masterchef365]

The first and worst way I can think of doing this is to just use the rust docker image, git clone the repo and build the server as needed. But that's more than a little wasteful - we should have an actual CI pipeline which pumps out releases for e.g. Windows, Linux, Macos, etc.

[Masterchef365]

Note that we at least have a script to build the server under docker using tools/compile_docker.sh. This doesn't have anything to do with deployment though...