Add recovery service.

RecoverySystemService is separated from PowerManagerService as a
dedicated system service to handle recovery related requests (such as
invoking uncrypt to uncrypt an OTA package on /data or to set up /
clear the bootloader control block (i.e. /misc) and etc).

The matching CL in frameworks/base is in:
  Change-Id: Ic606fcf5b31c54ce54f0ab12c1768fef0fa64560.

Bug: 26830925
Change-Id: Iee0583c458f784bfa422d0f7af5d1f2681d9609e
(cherry picked from commit 65b5fde9)