Keyboard Shortcuts UI - add shortcuts to dialog.

This is the first UI iteration which contains elements for
displaying the keyboard shortcuts. Is is by no means final,
the following items (and maybe more) still need to be actioned:

* no UI for phone
* no view for system shortcuts (which contain icons)
* the shortcut items container needs a custom layout which
  needs to wrap and right align elements (prototype done)
* find or build an util which can produce human readable
  names of the baseCharacter and the modifiers (so far I
  found a few functions, none of them good)
* not pixel-perfect
* the scrollbar does not show
* the last separator (before the DONE button) is not
  visible

Change-Id: I0d191e9516ab8f4728f40b3eefe9d854249ee7a8