99: Basic functioning of multiple workflow types per worker at once.

[lfse-slafleur]

No description provided.

[MarkTNO]

This approach is ok for now, also because this functionality is needed asap.

It does have a draw back since celery tasks do not interleave between queues. The queue which is added first will have the highest priority. Jobs from a specific queue will be executed only when all other higher priority queues (to which the task is connected) are empty. This is not desirable.
This could be solved by having a single queue per worker type (optimizer and simulator queue). This will mean a worker will be connected to a single queue. The added benefit of this is that workers are more flexible and job prioritization will work better.
This is quite some work since the queue names are now equal to the workflow type name.

Any other suggestions are welcome!