Added rules for xdg, gvfs, wl-clipboard and more...

[JohnRTitor]

In summary this PR:

• Adds XDG portal service rules
• Adds GVFS service rules
• Adds wl-clipboard rules
• Adds miscellaneous services like dconf, devmon, udisks, gpg, playerctld
• Adds NixOS equivalent process names for
  • Discord
  • Gnome Keyring
  • Telegram
  • Thunderbird

+1 Also imposes BG_CPUIO rule on chrome-crashpad-handler.

[JohnRTitor]

Pinging @ptr1337 for review.

[JohnRTitor]

I am confused as to what to put for playerctld. It is just a daemon for managing play pause and other actions, then forwarding them to the active player.
Would it be fine with something like Service on high system load? Player-Video has a way lower nice value and should allow those commands to pass without interruptions.