Settings: statusbar clock customization

- added slims clock and date customizations for status bar
- added initial interface settings. A bit empty currently but we are on
  alpha and it will be filled fast for sure. Added as well two empty
classes
  due that we need them later

Originally by @kufikugel. I just ported to 5.0

PS:
- small cleanups and adaptions to LP
- add personalization category on dash board.
- go inline with new default values on fb patch
- add correct dialog handling
- use correct reset icon
etc.