Frameworks: Hover options (1/2)

add some user options to the Hover feature:
  - enable/disable
  - hide Hover button
  - force require fullscreen
  - exclude nom clearable notifications
  - exclude low priority notifications
  - exclude foreground app
  - selectable timeout delay

option menu is shown on hover toggle longpress and is launched in a floating window
fragment calls settings preference as a setting shortcut

Change-Id: I96ce22f395f04b7a1a3dc44f8dfb1476e0e3d619