This change makes WebGL to use LibGL only in SerenityOS, and the
platform's OpenGL driver in Ladybird if it is available.
This is implemented by introducing wrapper class between WebGL and
OpenGL calls. This way it will also be possible to provide more
complete support in Ladybird even if we don't yet have all needed
calls implemented in LibGL.
For now, the wrapper class makes all GL calls virtual. However, we
can get rid of this and implement it at compile time in case of
performance problems.
