Fixes for Gymnasium API and various other improvements

[rk1a]

Summary

• Fixes remaining issues with Gymnasium API (metadata keys render_modes and render_fps, drop public seed() method, normalize mouse action space)
  • this should close Migrate from Gym to Gymnasium #69
• Registers base Minetest environment with the Gymnasium API
• Fixes bug where reset would not change world seed due to wrong config write order
• Adds useful graphics environment variables for
  • enabling Nvidia GPU rendering for minetest
  • disabling vsync -> allowing FPS > screen refreshing rate
• Adds logic for using minetest_headless binary. For now it is used if headless=True and start_xvfb=False
• Adds client-side dtimeargument
  • enables fixing in-game time per step
  • allows slowing down or speeding up game dynamics
  • makes dynamics (more) independent of used hardware

How to test

• Gymnasium API: python -m minetester.scripts.gymnasium_api_check should run without errors
• Graphics settings: python -m scripts.measure_fps should have increased FPS, especially when setting xvfb=False (with NVIDIA GeForce RTX 3050 Ti I get around 115 FPS)
• Custom dtime:
  • ./bin/minetest --dtime 0.001 --record --go --client-address "tcp:https://*:5555" --world worlds/test for slowmo
  • ./bin/minetest --dtime 0.1 --record --go --client-address "tcp:https://*:5555" --world worlds/test for time lapse

[JosiahWI]

Could you explain this PR changes the submodules URLs from SSH to HTTP?

[rk1a]

Could you explain this PR changes the submodules URLs from SSH to HTTP?

I think this made it easier to install the submodules when I set up the project on remote servers. Without changing this it required some sort of authorization with github, while http didn't need that

[AI-WAIFU]

Everything looks good, tested on a new machine and everything works nicely. Merging