compositor-drm: Add DRM property cache

Add a cache for DRM property IDs and values, and use it for the two
connector properties we currently update: DPMS and EDID.

As DRM property ID values are not stable, we need to do a name -> ID
lookup each run in order to discover the property IDs and enum values to
use for those properties. Rather than open-coding this, add a property
cache which we can use across multiple different object types.

This patch takes substantial work from the universal planes support
originally authored by Pekka Paalanen, though it has been heavily
reworked.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Co-authored-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>