Move headers from server/include to include/maxscale

- Headers now to be included as <maxscale/xyz.h>
- First step, no cleanup of headers has been made. Only moving
  from one place to another + necessary modifications.

include/maxscale/modinfo.h

@@ -0,0 +1,86 @@
+#ifndef _MODINFO_H
+#define _MODINFO_H
+/*
+ * 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.
+ */
+
+/**
+ * @file modinfo.h The module information interface
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date     Who             Description
+ * 02/06/14 Mark Riddoch    Initial implementation
+ *
+ * @endverbatim
+ */
+
+/**
+ * The status of the module. This gives some idea of the module
+ * maturity.
+ */
+typedef enum
+{
+    MODULE_IN_DEVELOPMENT = 0,
+    MODULE_ALPHA_RELEASE,
+    MODULE_BETA_RELEASE,
+    MODULE_GA,
+    MODULE_EXPERIMENTAL
+} MODULE_STATUS;
+
+/**
+ * The API implemented by the module
+ */
+typedef enum
+{
+    MODULE_API_PROTOCOL = 0,
+    MODULE_API_ROUTER,
+    MODULE_API_MONITOR,
+    MODULE_API_FILTER,
+    MODULE_API_AUTHENTICATOR,
+    MODULE_API_QUERY_CLASSIFIER,
+} MODULE_API;
+
+/**
+ * The module version structure.
+ *
+ * The rules for changing these values are:
+ *
+ * Any change that affects an inexisting call in the API in question,
+ * making the new API no longer compatible with the old,
+ * must increment the major version.
+ *
+ * Any change that adds to the API, but does not alter the existing API
+ * calls, must increment the minor version.
+ *
+ * Any change that is purely cosmetic and does not affect the calling
+ * conventions of the API must increment only the patch version number.
+ */
+typedef struct
+{
+    int     major;
+    int     minor;
+    int     patch;
+} MODULE_VERSION;
+
+/**
+ * The module information structure
+ */
+typedef struct
+{
+    MODULE_API  modapi;
+    MODULE_STATUS   status;
+    MODULE_VERSION  api_version;
+    char        *description;
+} MODULE_INFO;
+#endif