SystemUI: Customize StatusBar for Chinese carrier

1. Show carrier label in notification panel.
2. Add values-w320dp to adapt lower resolution device.
3. Update Chinese roaming string.
4. Show wifi activity in status bar.
5. Show indicator for Wifi on but not connected.
6. Show rsrp level for LTE.
7. Redesign the scheme of selecting icons on signal cluster.
   Customized SigalClusterView and MobileSignalController to adapt
   requirement from Chinese carriers. The customization is controller
   by config values defined in overlayed config.xml.

CRs-Fixed: 653747
Change-Id: I4b228cc4afa552b348a96302a4858a0ab0c7e7f0