Telephony: STK CC feature implementation

Add strings and constants required for stk cc feature

Change-Id: Id5ec987cdc8dc2d9eebdf01fe546eb96ec0c69f9

Conflicts:
core/res/res/values/strings.xml
Change-Id: Id5ec987cdc8dc2d9eebdf01fe546eb96ec0c69f9

Conflicts:
	telephony/java/com/android/internal/telephony/RILConstants.java