[Web][Restic][Dovecot][Dockerapi] Add restic backups with restore in the UI

- Scheduled, encrypted backups to S3, SFTP, REST or a local folder (new restic-mailcow container)
- Restore of mailboxes and whole domains in the UI, also deleted ones, for admins and domain admins
- Scope set by RESTIC_BACKUP_MODE in mailcow.conf (all, data, config)
- Optional backup before updates (update.sh), helper-scripts/restic.sh for a full restore

data/web/domainadmin/restore.php

@@ -0,0 +1,8 @@
+<?php
+require_once $_SERVER['DOCUMENT_ROOT'] . '/inc/prerequisites.inc.php';
+require_once $_SERVER['DOCUMENT_ROOT'] . '/inc/triggers.domainadmin.inc.php';
+
+protect_route(['domainadmin']);
+
+$role = "domainadmin";
+require_once $_SERVER['DOCUMENT_ROOT'] . '/inc/restore.inc.php';