Update use statement lists with new Friendica\Database\dba class

- Remove unused use statement
- Remove superfluous use statements (classes in the same namespace)
- Add missing use statements

mod/lostpass.php

@@ -4,8 +4,10 @@
  */
 
 use Friendica\App;
+use Friendica\Core\Config;
 use Friendica\Core\L10n;
 use Friendica\Core\System;
+use Friendica\Database\dba;
 use Friendica\Database\DBM;
 use Friendica\Model\User;
 use Friendica\Util\DateTimeFormat;