Adafruit.io compatible code for filaminder

This is updated code as taken from https://automatedhome.party/2020/01/30/updated-filaweigher-filament-scale-now-with-temperature-humidity-pressure-and-mqtt/

The instructions provided in his blog post are still relevant for the building of the hardware.

The code worked great, but adafruit.io offers grouping in MQTT, and as a result it means the URL's look like:

/username/feeds/groupname.topic

Unfortunately the original code would only allow for this:

/username/feeds/groupname/topic

I could have just modified the code to be adafruit.io compatible, but instead I added a new option for defining what the final separator is, which typically is going to be / or . but can be anything you need it to be.

Additionally I added some debugging to show what topics are being sent via MQTT, and I disabled the spam on the serial console for when the load cell value didn't change.

The nut STL file is only here because I have to have an STL to publish. It is unchanged from the ori