yaml config

Store configuration in yaml

BeagleBone support

• Add BeagleBone installation instructions
• Update Model to v2.3 - the last model that is small/fast enough for the Beaglebone

BirdNET Analyzer as a submodule

• pin the BirdNET Analyzer version

flutter web app

• Adding a flutter web app.
• Updates with the latest changes from python influx-client API.

RPI3 support, unit tests

• Add support for RPI3
• Add an override of config.py parameters for the microphone through the command line
• Add tox support
• Improve pytest coverage