Framebuffer object is allocated using OpenGL's API and is not platform
specific which means it could be used on both macOS and Linux unlike
EGL specific PBuffer.
This change introduces GL.h with error check wrappers for all the
OpenGL functions we used so far.
For now, the error check is simply:
`VERIFY(glGetError() == GL_NO_ERROR);`
but that is better than continuing execution after encounting an error.
This change introduces a new 2D graphics library that uses OpenGL to
perform painting operations. For now, it has extremely limited
functionality and supports only rectangle painting, but we have to
start somewhere.
Since this library is intended to be used by LibWeb, where the
WebContent process does not have an associated window, painting occurs
in an offscreen buffer created using EGL.
For now it is only possible to compile this library on linux.
Offscreen context creation on SerenityOS and MacOS will have to be
implemented separately in the future.
Co-Authored-By: Andreas Kling <awesomekling@gmail.com>
