Add custom carrier label functions, (2/2):

- Move "Custom carrier label" to Settings -> Interface - General
- Settings -> Interface - Status bar expanded -> Notification drawer -> carier and Wifi network name:

  - Add checkbox "Show"

- Settings -> Lock screen:

  - Add preference screen "Carrier label"

- Settings -> Lock screen -> Carrier label:

  - Add checkbox "Show"
  - Add color picker "Color"

- Some code cleanup
- Change Strings

Change-Id: I3234f2908cebc16605928e5ed7fddc1e6c23d21e