healthd: charger: Add tricolor led to indicate battery capacity

Add led to indicate battery capacity when doing off mode charging. The
led behavior is design as below:
   i. 	Shows red led if capacity is lower than 15%.
   ii.	Shows yellow (red + green) led if capacity is
	lower than 90% but higher than 15%.
   iii. Shows green led if capacity is higher than 90%.

Change-Id: If637defec8a04e859b00a6492ec1f95d6bff2200