restore MM functionality to not reset segments if 2D settings change!!!

customeffects.js:
- rename downloadCEFile to downloadGHFile
- downloadGHFile: add GH ledmaps folder

FX_fcn.cpp and set.cpp:
- change makeAutoSegments with resetSegments(true)

wled00/FX_fcn.cpp

@@ -2097,7 +2097,7 @@ bool WS2812FX::deserializeMap(uint8_t n) {
       Segment::maxWidth = p.width;
       Segment::maxHeight = p.height;
 
-      makeAutoSegments();
+      resetSegments(true); //WLEDMM not makeAutoSegments() as we only want to change bounds
     }
 
     customMappingSize  = map.size();