Temporarily additional stats into battery dumpsys

In dumpsys the following additional information is surfaced:
* Information regarding the current battery capacity as reported from
the battery info callback
* "Real" charge and power information reported from the IHealth HAL
* Per-uid Foreground power estimates

Bug: 169376495
Test: builds
Test: dumpsys batterystats
Change-Id: I90722f349b87d5102afa48e0bd32b04840691364