Finish building and test the command controller, socketio and DataAccess

The command controller is there to dispatch commands to the vehicles and get send back the response.

From the vehicle side it needs to be possible to subscribe to get new commands, request to be send all not executed commands at a later point, in case they get lost and to send back the result of the command.

Most of this is already build though some improvements and testing has to be done:
- Investigate if its a good idea to attach the type information somewhere (i.e. store how the command and the response data need to look like, so it's clear to i.e. the frontend how to display stuff)
- Have a look if the DataAccess is ordering the commands correctly (by time, etc.)