[WIP] Burgwar Docker image - Xmake compatible version

[Elanis]

This is the first working version of Docker image.

How to test it ?

• git clone the folder
• Build image with docker build --tag burgwar-server:latest .
• Run server:

  docker run -ti --rm --name=burgwar-server -p 14768:14768/udp \
  -v /relativeOrAbsolute/path/to/assets:/srv/assets/ \
  -v /relativeOrAbsolute/path/to/mods:/srv/mods/ \
  -v /relativeOrAbsolute/path/to/scripts:/srv/scripts/ \
  -v /absolute/path/to/serverconfig.lua:/srv/serverconfig.lua \
  burgwar-server:latest

  Warning: If you are using Docker Desktop on Windows, you should execute this command under a WSL console. Executing with Git bash for example won't work.

TO DO before merge

• [x] use /home/burgwar instead of /home/burgwar/BurgWar
• [x] use default xmake.lua
• [x] Only keep artifacts to make a light image
• [x] Set server path in runtime image to /srv/
• [x] stop using git clone and use local repo ?

Next steps

• Use alpine linux instead of debian for runtime image (#65)
• CI (#67)
• remove nazara legacy apt when we migrated (#66)

[CLAassistant]

All committers have signed the CLA.

[SirLynix]

Thanks!