Add statusbar transparency mode, statusbar style menu, and statusbar color code cleanup

Statusbar transparency mode:
- home
- keyguard and home (default)
- always

Statusbar style menu:
- reset

Statusbar transparency mode and statusbar style menu is ported from SlimRoms,
Statusbar color code cleanup is ported/inspired from SlimRoms:

https://github.com/SlimRoms/packages_apps_Settings/commit/108f991efa82ece17c97cb5a49db63b984dfb38e