Make maxutils a standalone library

The only way to cleanly separate the maxutils library from the MaxScale
CMake project is to make it a standalone CMake project. With the help of
ExternalProject, it should be relatively easy to use.

maxutils/maxbase/include/maxbase/CMakeLists.txt

@@ -0,0 +1,10 @@
+set(TYPES "*.h" "*.hh")
+foreach(type ${TYPES})
+  file(GLOB HEADERS ${type})
+  foreach(var ${HEADERS})
+    get_filename_component(header ${var} NAME)
+    install(FILES ${header} DESTINATION include/maxbase)
+  endforeach()
+endforeach()
+
+