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/util.cpp

@@ -369,7 +369,6 @@ void checkSettingsPIN(const char* pin) {
   if (!correctPIN && millis() - lastEditTime < PIN_RETRY_COOLDOWN) return; // guard against PIN brute force
   bool correctBefore = correctPIN;
   correctPIN = (strlen(settingsPIN) == 0 || strncmp(settingsPIN, pin, 4) == 0);
-  if (correctBefore != correctPIN) createEditHandler(correctPIN);
   lastEditTime = millis();
 }