Restore without the recovery kit: the key from the location, with a passphrase

On a server without a backup key, backup:target:add finds the backups at
the location and takes their key from its config with one of the old
server's passphrases. Backups then wait until a new recovery kit is
confirmed. The deletion delay and the repository id are now stored on the
location, sealed with the key, so the delay survives a restore without a
kit and --repair-config can write a lost config again from the kit.

The key page warns against creating a new key when restoring a server.
New test: tests/integration/recovery-scenarios.sh, and a no-kit mode in
full-restore-roundtrip.sh.

lib/Service/BackupService.php

@@ -225,6 +225,8 @@ final class BackupService {
 				if (!isset($state['dump'])) {
 					// It may have been queued for hours: the restore point has the time of its data.
 					$state['files']['started'] = gmdate('c');
+					// Locations from before 1.1.0 get their sealed settings at their next backup.
+					$this->targets->recordSettings($repo);
 				}
 				$dumper = new DbDumper($this->db->getInner(), $this->config->getSystemValueString('dbtableprefix', 'oc_'));
 				$dbStats = $state['dbStats'] ?? [];