Add modified Replicator for avrorouter

Repurposed the Replicator from the CDC integration project as a
replication event processing service. It is similar to the CDC version of
the Replicator and is still in the same namespace but it lacks all of the
cross-thread communication that was a part of the integration project.

server/modules/routing/avrorouter/config.hh

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2019 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2022-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#pragma once
+
+#include <chrono>
+#include <string>
+#include <unordered_set>
+#include <vector>
+
+#include <maxscale/service.hh>
+
+#include "rpl.hh"
+
+namespace cdc
+{
+
+struct Server
+{
+    std::string host;       // Address to connect to
+    int         port;       // Port where the server is listening
+    std::string user;       // Username used for the connection
+    std::string password;   // Password for the user
+};
+
+struct Config
+{
+    int         server_id = 1234;   // Server ID used in registration
+    std::string gtid;               // Starting GTID
+    SERVICE*    service;
+    std::string statedir = ".";
+};
+}