Peek in segment tab

Move peek 2D functionality to peek.js

FX_fcn.cpp: always erase customMappingTable if non existent ledmap

wled_server.cpp: add peek.js

index.js:
- add canvasPeek
- change resize of canvas

wled00/wled_server.cpp

@@ -288,6 +288,14 @@ void initServer()
     request->send(response);
   });
 
+  //WLEDMM
+  server.on("/peek.js", HTTP_GET, [](AsyncWebServerRequest *request){
+    AsyncWebServerResponse *response = request->beginResponse_P(200, "application/javascript", PAGE_peekJs, PAGE_peekJs_length);
+    response->addHeader(FPSTR(s_content_enc),"gzip");
+    setStaticContentCacheHeaders(response);
+    request->send(response);
+  });
+
   createEditHandler(correctPIN);
 
 #ifndef WLED_DISABLE_OTA