Draft: testing/usbguard: enable polkit and dbus support, rules.d dir
AFAIK polkit and dbus support are required for some GUI interfaces to usbguard, e.g. GNOME.
This also enables the rules folder support, so multiple rules can be installed
into /etc/usbguard/rules.d/
. This is useful for downstream Alpine distros
(postmarketOS), and folks who like to organize config/rules differently than
having a single rule.conf file.