Improving docker dev environment (adding the backend)

[AlexandreOndet]

Right now the docker-compose only contains the frontend and nginx. Simply adding the flask service doesn't allow the container to reach the emulator on the host. We will need to figure out a way to make it work.
Possible solutions:

• Put the emulator in a container
• Put the emulator in the python container (not great)

The end goal is to have the whole dev environment running with just one command (docker-compose up)