Debate bundling libOpenGL

[JulianGro]

While the AppImage devs have put libOpenGL.so* on the excludelist, I do not see any reason for why it couldn't be included. libGLdispatch might also need to be bundled since libOpenGL is just a wrapper for it. libGLdispatch should work fairly independent from the distribution as its whole point is to find and expose different vendors' libraries.

The real riddle for me is why modern Linux distributions wouldn't provide full OpenGL support in the first place.
Maybe we should check which distributions provide libOpenGL and which don't?
Ubuntu 20.04 and PopOS 20.04 (which is based on Ubuntu 20.04) do not provide libOpenGL. While they don't provide libOpenGL, they do provide libGL which is only supposed to be used for legacy programs that don't link to libOpenGL.
As I haven't seen any libOpenGL errors when we switched to GLVND, it is also possible that Ubuntu 18.04 did have libOpenGL installed by standard and Canonical removed this in Ubuntu 20.04.