MXS-2220 Move most remaining functions inside class

Most of the ones still remaining outside are special cases.
Also, removed locking from status manipulation functions as it
has not been required for quite some time.

server/core/internal/server.hh

@@ -175,6 +175,14 @@ public:
      */
     static Server* create_test_server();
 
+    /**
+     * Deallocate the specified server
+     *
+     * @param server        The server to deallocate
+     * @return Returns true if the server was freed
+     */
+    static void server_free(Server* server);
+
     /**
      * @brief Find a server with the specified name
      *
@@ -289,7 +297,7 @@ public:
      *
      * @return True, if the provided string is valid and the threshold could be set.
      */
-    bool server_set_disk_space_threshold(const char* disk_space_threshold);
+    bool set_disk_space_threshold(const char* disk_space_threshold);
 
     /**
      * Print all servers
@@ -367,8 +375,6 @@ private:
     maxbase::EMAverage m_response_time;     /**< Response time calculations for this server */
 };
 
-void server_free(Server* server);
-
 /**
  * @brief Convert a server to JSON format
  *