Pekka Paalanen authored Mar 16, 2022 and Pekka Paalanen committed May 27, 2022

This adds an option to program basic display color characteristics from
weston.ini. In the future there will be a way to set this information
from EDID, but because EDID is unreliable that will probably not be the
default. An ICC profile will likely override most or all of this. The
main reason to add this option is to be able to characterise HDR
monitors.

An 'output' section can have a key 'color_characteristics' (string)
set to a name. The name refers to any 'color_characteristics' section
with 'name' set to the same string.

The 'name' key of a 'color_characteristics' section cannot contain a
colon ':'. Names with colon in 'output' section key
'color_characteristics' value are reserved for future use, e.g. to
indicate that the metadata is to be taken from EDID instead of a
weston.ini section.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>