Power Monitor Addition frameworks telephony:

Adding additional fields to telephony metrics to record the power
monitored on cellular rails. This metric will allow us to better isolate
where our actual power usage is during modem use cases. This can be
directly compared with ModemPowerStats energyConsumedMah. Thus, having
this metric in telephony stats is vital in the comparsion on already
calculated power usage. BatteryStats collects and reports the power
monitored rail data to telephony metrics using ModemPowerMetrics.

If a device does not support rail power monitoring then this value may
remain at 0.

Bug: 115929961
Test: adb shell dumpsys activity service TelephonyDebugService --metrics
Results Examples:
        Energy consumed by modem (mAh): 2.41
        Energy consumed across measured modem rails (mAh): 2.76
Dumpsys Example:
	  +4m23s712ms (2) 100 cc511a18 modemRailChargemAh=0.34 wifiRailChargemAh=1.17 +wifi_scan stats=0:"dump"
         +10m24s089ms (2) 100 c4511a18 modemRailChargemAh=0.71 wifiRailChargemAh=1.77 stats=0:"write"
         +11m24s228ms (3) 100 c4511a19 volt=4315 charge=3988 modemRailChargemAh=0.77 wifiRailChargemAh=1.94 wifi_signal_strength=2 stats=0:"battery-state"

Change-Id: I2b1a20950e118f675fed45b40785128477711268