Move all routers into subdirs of their own

Each router module now resides in a subdirectory of its own.
The name of the subdirectory is the same as the name of the
library in the module's CMakeLists.txt file.

server/modules/routing/testroute/CMakeLists.txt

@@ -0,0 +1,4 @@
+add_library(testroute SHARED testroute.c)
+target_link_libraries(testroute maxscale-common)
+set_target_properties(testroute PROPERTIES VERSION "1.0.0")
+install_module(testroute core)

server/modules/routing/testroute/testroute.c

@@ -0,0 +1,181 @@
+/*
+ * 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/bsl.
+ *
+ * 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 <stdio.h>
+#include <maxscale/alloc.h>
+#include <router.h>
+#include <modinfo.h>
+
+static char *version_str = "V1.0.0";
+
+MODULE_INFO     info =
+{
+    MODULE_API_ROUTER,
+    MODULE_IN_DEVELOPMENT,
+    ROUTER_VERSION,
+    "A test router - not for use in real systems"
+};
+
+static  ROUTER *createInstance(SERVICE *service, char **options);
+static  void   *newSession(ROUTER *instance, SESSION *session);
+static  void   closeSession(ROUTER *instance, void *session);
+static  void   freeSession(ROUTER *instance, void *session);
+static  int    routeQuery(ROUTER *instance, void *session, GWBUF *queue);
+static  void   clientReply(ROUTER *instance, void *session, GWBUF *queue, DCB*);
+static  void   diagnostic(ROUTER *instance, DCB *dcb);
+static  int    getCapabilities ();
+static void    handleError(ROUTER           *instance,
+                           void             *router_session,
+                           GWBUF            *errbuf,
+                           DCB              *backend_dcb,
+                           error_action_t   action,
+                           bool             *succp);
+
+static ROUTER_OBJECT MyObject =
+{
+    createInstance,
+    newSession,
+    closeSession,
+    freeSession,
+    routeQuery,
+    diagnostic,
+    clientReply,
+    handleError,
+    getCapabilities
+};
+
+typedef struct
+{
+} TESTROUTER;
+
+typedef struct
+{
+} TESTSESSION;
+
+/**
+ * Implementation of the mandatory version entry point
+ *
+ * @return version string of the module
+ */
+char *
+version()
+{
+    return version_str;
+}
+
+/**
+ * The module initialisation routine, called when the module
+ * is first loaded.
+ */
+void
+ModuleInit()
+{
+
+}
+
+/**
+ * The module entry point routine. It is this routine that
+ * must populate the structure that is referred to as the
+ * "module object", this is a structure with the set of
+ * external entry points for this module.
+ *
+ * @return The module object
+ */
+ROUTER_OBJECT *
+GetModuleObject()
+{
+    return &MyObject;
+}
+
+/**
+ * Create an instance of the router for a particular service
+ * within the gateway.
+ *
+ * @param service   The service this router is being create for
+ * @param options   The options for this query router
+ *
+ * @return The instance data for this new instance
+ */
+static  ROUTER  *
+createInstance(SERVICE *service, char **options)
+{
+    return (ROUTER*)MXS_MALLOC(sizeof(TESTROUTER));
+}
+
+/**
+ * Associate a new session with this instance of the router.
+ *
+ * @param instance  The router instance data
+ * @param session   The session itself
+ * @return Session specific data for this session
+ */
+static  void    *
+newSession(ROUTER *instance, SESSION *session)
+{
+    return (SESSION*)MXS_MALLOC(sizeof(TESTSESSION));
+}
+
+/**
+ * Close a session with the router, this is the mechanism
+ * by which a router may cleanup data structure etc.
+ *
+ * @param instance  The router instance data
+ * @param session   The session being closed
+ */
+static  void
+closeSession(ROUTER *instance, void *session)
+{
+}
+
+static void freeSession(
+    ROUTER* router_instance,
+    void*   router_client_session)
+{
+    MXS_FREE(router_client_session);
+}
+
+static  int
+routeQuery(ROUTER *instance, void *session, GWBUF *queue)
+{
+    return 0;
+}
+
+void clientReply(ROUTER* instance, void* session, GWBUF* queue, DCB* dcb)
+{
+}
+
+/**
+ * Diagnostics routine
+ *
+ * @param   instance    The router instance
+ * @param   dcb     The DCB for diagnostic output
+ */
+static  void
+diagnostic(ROUTER *instance, DCB *dcb)
+{
+}
+
+static int getCapabilities()
+{
+    return 0;
+}
+
+
+static void handleError(
+    ROUTER           *instance,
+    void             *router_session,
+    GWBUF            *errbuf,
+    DCB              *backend_dcb,
+    error_action_t   action,
+    bool             *succp)
+{
+}