Add get command.

Add a get command to get the various properties of the battery state.

Also fix help output:
1. The command to disable charging is "suspend_input" not "disable_charge".
2. Also, add the `counter` key for the set command.

Bug: 167636754
Bug: 214599394
Test: adb shell cmd battery
Test: Test: atest --rerun-until-failure 25 CtsJobSchedulerTestCases:android.jobscheduler.cts.JobThrottlingTest#testJobsInRestrictedBucket_DeferredUntilFreeResources
Change-Id: Iac1351441679516693f3b676fa079be71de46a7c