Godot-4.0.2 with Bullet physics support

Godot development team has dropped Bullet physics support in favor of their custom physics engine in Godot version 4. However, their custom physics is unstable and blows up sometimes. This executable is a port of Bullet physics to Godot 4.

Appropriate source code can be obtained from the source repo git@github.com:z80/ignition.git, commit b49f801f3.