DeviceState: Add a 2nd stage initialization

To solve a circular dependency of multiple system services, add
a 2nd stage initialization so that DeviceState can depend on
services that are initialized after it.

onBootPhase is inherited from SystemService and PHASE_SYSTEM_SERVICES_READY indicates all services are ready to
be used.

Bug: 378932403
Change-Id: Ifb2b12b9786a7656d7a1cff6070804dc2a0ebc37
Test: Update image to AL. Check log & check cmd device_state
Flag: EXEMPT bugfix