incidentd: Updating PowerManagerService proto files.

Moving to the proto/.../server directory since PowerManagerService is in
com.android.server.
Extracting enums from other components into their own files.

Bug: 65750826
Bug: 65750806
Test: flash device and check incident.proto output
Change-Id: Ib91b7c08142fa66adf18b6e85106d4cbb5adf660