Add skeleton hint router

The hint router will perform its scheduling solely based upon hints
provided by a filter (e.g. namedserverfilter) placed before it.

server/modules/routing/hintrouter/hintrouter.hh

@@ -0,0 +1,36 @@
+#pragma once
+/*
+ * Copyright (c) 2016 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: 2019-07-01
+ *
+ * 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.
+ */
+
+#include <maxscale/cppdefs.hh>
+#include <maxscale/router.hh>
+#include "hintroutersession.hh"
+
+class HintRouter : public maxscale::Router<HintRouter, HintRouterSession>
+{
+public:
+    static HintRouter* create(SERVICE* pService, char** pzOptions);
+
+    HintRouterSession* newSession(MXS_SESSION *pSession);
+
+    void diagnostics(DCB* pOut);
+
+    uint64_t getCapabilities();
+
+private:
+    HintRouter(SERVICE* pService);
+
+private:
+    HintRouter(const HintRouter&);
+    HintRouter& operator = (const HintRouter&);
+};