Add ESP32 bootloader upgrade functionality with JSON API support

Co-authored-by: netmindz <442066+netmindz@users.noreply.github.com>

wled00/json.cpp

@@ -817,6 +817,9 @@ void serializeInfo(JsonObject root)
   root[F("resetReason1")] = (int)rtc_get_reset_reason(1);
   #endif
   root[F("lwip")] = 0; //deprecated
+  #ifndef WLED_DISABLE_OTA
+  root[F("bootloaderSHA256")] = getBootloaderSHA256Hex();
+  #endif
 #else
   root[F("arch")] = "esp8266";
   root[F("core")] = ESP.getCoreVersion();