Cleaned up Docker compose file

[jlaacke]

• Removed voorwiel from docker compose file since it is always built separately
• Always restart cykel related docker containers to use them like daemon processes
• Removed ALLOWED_HOSTS, since they are configured via .env file

[robbi5]

Thanks for the PR :)
Just one question: do you have a special reason to add the api/stations/location endpoint for gps coordinates of stations, or could you use the ones already provided by the station_information.json from GBFS (https://github.com/stadtulm/cykel/blob/master/gbfs/serializers.py#L62)?

[jlaacke]

@robbi5 You are absolutely right, we don't need an additonal API for that. So I removed that and changed the title of the PR. ;) The voorwiel PR is ready to go: transportkollektiv/voorwiel#28