Add --avb_recovery_* options to replace recovery avb key

Test: run sign_target_files_apks with --avb_recovery_key to specify a different key and check with avbtool the key was replaced
Bug: 210126985
Signed-off-by: Ben Fennema <fennema@google.com>
Change-Id: Ic2bb3f6855a49ec065a4c778c429ff076902b95c