Apps: New Driver, Disk icon, update some styles

New
- Additional Drivers (jockey), uses application-x-firmware mimetype as base
- Gnome Disk Utility, using official disk app but add border making it easier to see (fixes shimmerproject#215)

Updated
- USB Creator / Ubiquity, new arrow type and gradients
- Keyring, use semi-transparent borders (sharper on dark backgrounds)

Removed / Changed
- Use old totem icon for Xine and remove Xine symlink (totem icon wasn't being used)