debian: Add AppArmor rules for network, Frampton, Canterbury, GVFS

This fleshes out the Prestwood AppArmor profile a little, fixing most of
the AppArmor ALLOWED messages I see in the journal after booting. It
does not fix the ALLOWED messages for the currently-unconfined parts of
GVFS which Prestwood uses.

It adds:
 • abstractions/namespace to allow network access for UPnP shares
 • Access for Canterbury’s media manager to query mounts and shares
 • Similarly for Frampton
 • Access to GVFS for remote volume monitoring

Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Signed-off-by: Philip Withnall <philip.withnall@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D3554