Add thermal status API for app and unit test

Test: Manually on Thermal HAL 2.0 device
Test: Manually on Thermal HAL 1.1 device
Test: Manually on no Thermal HAL emulator
Test: atest $ANDROID_BUILD_TOP/frameworks/base/services/tests/servicestests/src/com/android/server/power/ThermalManagerServiceTest.java
Bug: 111086696
Bug: 119413961
Change-Id: I6723406123d12339e82e9e87eec14b7f9a301897