Ignore Chef client/cache files
Chef: cleanup/consolidate packages calls

Loops/arrays are much tidier than repetition.
Chef: fix overlength lines
Chef: remove apt-get updates after apt_repository calls

These aren't necessary now apt_repository notifies apt-get-update for
us.
Chef: add missing metadata file to cookbook
Chef: remove duplicate newline
Chef: gnome_terminal: totally change dconf sorcery

dconf changes are still getting reverted seemingly randomly, so we'll try just
dumping the entire /org/gnome/terminal/ key. Hopefully this will finally fix
it.