Bug 33360: Extend Koha::Notice::Util with domain groups

Bug 33360: Extend Koha::Notice::Util with domain groups

The functionality is extended a bit here by:
[1] Allowing to combine domains in a shared count.
[2] Only counting sent messages for the specified
    domains when it is really needed.

Test plan:
Run t/db_dependent/Koha/Notice_Util.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>