More OpenGL refactors
For details see the individual commits, but the rough goal of most commits in here is to simplify and reduce usage of GLPlatform
, which gets in the way when multiple contexts are involved (like in the drm backend right now). I'll do more for that in future MRs.
Note that I haven't tested this on X11 yet because my X11 sessions (5.27 and dev) doesn't start for some reason