[virglrenderer-devel] features rework part 3 (ignore part 2)

[Dave Airlie]

This contains the part 2 work in it, and moves nearly all the
remaining code to using the features frameworks and tries to
clamp down any places we might access a GL API that isn't applicable
to the framework.

This series doesn't always dtrt for GLES3 hosts so I suspect,
we will need a rebase/rework of Gert's code once this lands.

I also need to test this a bit more, I suspect.
Dave.