Quick-start script should only pull the docker containers it actually starts up

[maxalbert]

Currently the quick-start script will pull all FlowKit containers, but will only spin up selected ones depending on the argument given by the user.

Example:

$ bash <(curl -s https://raw.githubusercontent.com/Flowminder/FlowKit/master/quick_start.sh)
Starting containers (this may take a few minutes)
Pulling flowdb                   ... done
Pulling flowdb_testdata          ... done
Pulling flowdb_synthetic_data    ... done
Pulling worked_examples          ... done
Pulling flowapi                  ... done
Pulling flowauth                 ... done
Pulling flowmachine_query_locker ... done
Pulling flowmachine              ... done
Pulling flowetl                  ... done
Pulling flowetl_db               ... done
[...]
Creating flowmachine_query_locker ... done
Creating flowauth                 ... done
Creating flowapi                  ... done
Creating flowdb_testdata          ... done
Creating flowmachine              ... done
[...]

To reduce the startup time and network bandwith used, it would be good if only the images that are actually required are pulled.