Restart policies: Add testing and ProcFS DB

 - Expose in procfs the service status and supported recovery policies.
 - This adds a test (testrelpol.sh) to exercise the restart policies of
   the system services and drivers.

NOTE:
  The policy support information is temporarily hardcoded in ProcFS, but
  this has to be replaced by properly retrieving this information from
  RS, which should in turn be setup on a per service basis, at
  initialization time.

Change-Id: I0cb1516a450355b38d0c46b1a8b3d9e841a2c029