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/core/config.c

@@ -50,30 +50,30 @@
 #include <stdlib.h>
 #include <ctype.h>
 #include <ini.h>
-#include <maxconfig.h>
-#include <dcb.h>
-#include <session.h>
-#include <service.h>
-#include <server.h>
-#include <users.h>
-#include <monitor.h>
-#include <modules.h>
-#include <skygw_utils.h>
-#include <log_manager.h>
+#include <maxscale/maxconfig.h>
+#include <maxscale/dcb.h>
+#include <maxscale/session.h>
+#include <maxscale/service.h>
+#include <maxscale/server.h>
+#include <maxscale/users.h>
+#include <maxscale/monitor.h>
+#include <maxscale/modules.h>
+#include <maxscale/skygw_utils.h>
+#include <maxscale/log_manager.h>
 #include <mysql.h>
 #include <sys/utsname.h>
 #include <sys/fcntl.h>
 #include <glob.h>
 #include <sys/ioctl.h>
 #include <net/if.h>
-#include <housekeeper.h>
-#include <notification.h>
+#include <maxscale/housekeeper.h>
+#include <maxscale/notification.h>
 #include <unistd.h>
 #include <netinet/in.h>
 #include <string.h>
 #include <sys/utsname.h>
-#include <dbusers.h>
-#include <gw.h>
+#include <maxscale/dbusers.h>
+#include <maxscale/gw.h>
 #include <maxscale/alloc.h>
 #include <maxscale/limits.h>
 #define PCRE2_CODE_UNIT_WIDTH 8