OTA and Status LED

This release includes improved stability for the watchdog timer issue as well as self-recovery for most crashes. Configurable LWT topic will allow you to detect device crashes and sensor states for each device on your network.

Over-the-Air updates are now possible from the command line of PlatformIO. You will need to know the IP address of the relevant device. This information should be available from your network router, or from the serial monitor after the device connects to a WiFi network.

Finally, the on-board LED now indicates status. For the most part, it will remain off, only lighting for 100ms when a device is detected on scan, or when the device is updating via OTA or is disconnected from the network.