dri: introduce dmabuf format modifier related handles

dri: introduce dmabuf format modifier related handles

these allow dmabuf import with modifiers, and supported format and
modifier queries, which are used to implement
EGL_EXT_image_dma_buf_import_modifiers.

v2:
- squash dmabuf queries into DRIimage version 15 (Jason Ekstrand).
- add external_only param to queryDmaBufModifiers (Emil, Daniel Stone)
- pass a single modifier form createImageFromDmaBufs2 since all planes have
the same modifier (Jason Ekstrand)

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Signed-off-by: Varad Gautam <varad.gautam@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>