Update BSL CR as long as there is any error

1. Mark the BSL as "Unavailable" when gets any error
2. Add a new field "Message" to the BSL status to record the error message

Fixes #4485
Fixes #4405

Signed-off-by: Wenkai Yin(尹文开) <yinw@vmware.com>

config/crd/v1/bases/velero.io_backupstoragelocations.yaml

@@ -158,6 +158,10 @@ spec:
                 format: date-time
                 nullable: true
                 type: string
+              message:
+                description: Message is a message about the backup storage location's
+                  status.
+                type: string
               phase:
                 description: Phase is the current state of the BackupStorageLocation.
                 enum: