Add status bar background and navigation bar styles, (1/2)

Reorganize preference screen status bar:

- Add prefernece screen "Styles"
- Add prefernece screen "Background"
(... -> Styles)

Added preference screen "Navigation",
(settings -> System)

Statusbar background styles:

- Custom color
- Custom transparency
- Transparency mode

Navigation bar styles:

- Custom color
- Custom height, (portrait)
- Custom weidth, (landscape)

Change-Id: I44fd00de9258952fb43721908a01588cc5c0e2c3