canterbury-full is the full version, while canterbury-common contains
supporting files like canterbury-exec that will also be needed on
minimal images.

There is no canterbury-core package yet, because that will contain
an alternative daemon that also depends on canterbury-common. At the
moment all the non-GUI-related tests only require canterbury-common.

The GSettings schema is only shipped in -full for now, and not
in -common. This is because it's currently only needed for one feature,
namely the LaunchPreferences() method, which is part of the -full
feature set. If Canterbury gains other configurables, we can move it
into -common with an appropriate Breaks/Replaces at that point.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Frédéric Dalleau <frederic.dalleau@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D6612