This is part of the Vulkan task T68990.
This commits changes a few things:
- Rename extensions to capabilities (but left the file name untouched).
- Cubemap mip render workaround detection is rewritten using gl
commands to avoid using the GPU API before initialization.
- Put all the capabilities that are only relevant for the GL backend
inside GLContext as static variables.
- Cleanup the names of the limit variables.
- Separate all GL related workaround search inside the GL module.
This is in preparation of vulkan backend. We move all opengl
functionnalities behind an abstract class.
This also cleansup the "dynamic" ubo create and rename it to
`GPU_uniformbuf_from_list()`
Contains, no functional change.
Part of T68990 Vulkan support.
