Rename the enums that are supposed to match OBD2 values to have an Obd2 prefix

Rename the enums that are supposed to match OBD2 values to have an Obd2 prefix
Rename the enums that contain a list of sensors and don't directly map to OBD2 to have a Diagnostic prefix

Test: clean build and flash, then
runtest -x packages/services/Car/tests/android_car_api_test/src/android/car/apitest/CarDiagnosticManagerTest.java
runtest -x packages/services/Car/tests/carservice_test/src/com/android/car/test/CarDiagnosticManagerTest.java
runtest -x packages/services/Car/tests/vehiclehal_test/src/com/android/car/vehiclehal/test/Obd2FreezeFrameTest.java
runtest -x packages/services/Car/tests/vehiclehal_test/src/com/android/car/vehiclehal/test/Obd2LiveFrameTest.java

Bug: 64024685
Change-Id: I9147bcd8f2972dee9f3d1e62f8978b595d88f606