recovery: report compliant reboot reason (Part Deux)

shutdown and reboot should have a corresponding sub-reason.

Adding:
    "reboot,userrequested,fastboot"
    "reboot,userrequested,recovery"
    "reboot,userrequested,recovery,ui"
    "shutdown,userrequested,fastboot"
    "shutdown,userrequested,recovery"
    "reboot,unknown#" (Can't happen, debug)

Test: manual, multiple targets, enter recovery, be able to exit recovery
Bug: 133326470
Change-Id: Ibfcb2a23158e8e99922e8053edd815fb592150f2