[Server] Expose the audit log on the database interface

addAuditRecord existed only on Servatrice_DatabaseInterface, so 37 moderator and admin commands reached through the concrete class just to append a log row. Declare it on Server_DatabaseInterface with an empty default, mark the Servatrice implementation as an override, and switch the handler's call sites to the injected interface. No SQL moves; the argument hashes are unchanged.

servatrice/src/servatrice_database_interface.cpp

@@ -3320,7 +3320,7 @@ void Servatrice_DatabaseInterface::addAuditRecord(const QString &user,
                                                   const QString &clientid,
                                                   const QString &action,
                                                   const QString &details,
-                                                  const bool &results = false)
+                                                  bool results)
 {
     if (!checkSql()) {
         return;