Add STT to wazo-calld

Installation

For Google:

pip3 install google-cloud-speech

For AlloMedia:

Check https://allo-media.github.io/live-api-doc/getting-started/python.html

To install plugin:

wazo-plugind-cli -c "install git https://github.com/sboily/wazo-hackathon-wazo-calld-module"