Add BepInEx6 IL2CPP port

[ManlyMarco]

Requires BepInEx6 bleeding edge build 664 or newer. At the moment only works if UnityEngine.IMGUIModule is not stripped down, which is rare. Codebases also aren't merged yet.

[Loeffeldude]

At the moment only works if UnityEngine.IMGUIModule is not stripped down, which is rare.

Is there any workaround to this?

[ManlyMarco]

Is there any workaround to this?

Either one of the three:
1 - If it's not too badly stripped then it can be patched back like it is for HC, but it'll not be fully portable.
2 - The unstripper used in BepInEx needs to be improved.
3 - A different UI framework has to be used like dear imgui.