Request: CUPS Snap ("cups") auto connection to avahi-control, raw-usb, cups-control, and system-files interfaces

All in all, following 6 interfaces need to get auto-connected by the “cups” Snap:

  • avahi-control
  • raw-usb
  • cups-control
  • system-config
  • cups-domain-socket
  • cups-config

The first two are already automatically connecting in printing-stack-snap, the third is designed here, and the last three are all based on system-files and defined in snapcraft.yaml.