homed: add missing capabilities for SMB/CIFS backend

In 2020 mount.cifs started to require a bunch for caps to work. let's
add them to the capability bounding set.

Also, SMB support obviously needs network access, hence open that up.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1962920
(cherry picked from commit 16976433)