Add wakelock anomaly detector

This cl detects whether apps hold wakelock for long time.
For now we use the following attribute:
1. Longest total duration time among all the wakelocks
for one app.

Following cl will:
1. Get threshold from server side.
2. Add more attributes to make the detection more robust.

Bug: 36925184
Test: RunSettingsRoboTests

Change-Id: I1946faf69c363f6aa823d0005d6e03bc9082c085