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.

server/modules/monitor/mysqlmon.h

@@ -16,19 +16,19 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <monitor.h>
-#include <spinlock.h>
-#include <thread.h>
+#include <maxscale/monitor.h>
+#include <maxscale/spinlock.h>
+#include <maxscale/thread.h>
 #include <mysql.h>
 #include <mysqld_error.h>
-#include <skygw_utils.h>
-#include <log_manager.h>
-#include <secrets.h>
-#include <dcb.h>
-#include <modinfo.h>
-#include <maxconfig.h>
-#include <externcmd.h>
-#include <hashtable.h>
+#include <maxscale/skygw_utils.h>
+#include <maxscale/log_manager.h>
+#include <maxscale/secrets.h>
+#include <maxscale/dcb.h>
+#include <maxscale/modinfo.h>
+#include <maxscale/maxconfig.h>
+#include <maxscale/externcmd.h>
+#include <maxscale/hashtable.h>
 
 /**
  * @file mysqlmon.h - The MySQL monitor