Add GNOME extension AATWS

[mloskot]

Installer for https://github.com/G-dH/advanced-alttab-window-switcher - kudos @G-dH!

Custom configuration to set with gsettings:

• Common
  • Default Monitor > Monitor with focused windows
  • Show Favorite Apps When No Window Open > Disabled
  • Show Hotkeys F1-F12 for Direct Activation
  • Show Status > Enabled
• Window Switcher
  • Default Filter > Current Monitor
  • Window Preview Size (px) > 256
  • Window Icon Size (px) > 64
• ...