New file editor (#4956)

- no mendatory external JS dependency, works in offline mode
- optional external dependency is used for highlighting JSON, plain text edit is used if not available
- WLED styling (dark mode only)
- JSON files are displayed "prettyfied" and saved "minified"
- JSON color highlighting (if available)
- JSON verification during edit and on saving both in online and offline mode
- special treatment for ledmap files: displayed in aligned columns (2D) or as lines (1D), saved as minified json: no more white-space problems
- displays file size and total flash usage

wled00/set.cpp

@@ -613,7 +613,6 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
       #ifndef WLED_DISABLE_OTA
       aOtaEnabled = request->hasArg(F("AO"));
       #endif
-      //createEditHandler(correctPIN && !otaLock);
       otaSameSubnet = request->hasArg(F("SU"));
     }
   }