Use Celery workers in the run/map function calls (Voyager)

[bisgaard-itis]

The run/map endpoints for the function section of the api-server should be run as tasks in a celery worker associated with the api-server in order to increase stability of those endpoints and avoid overloading the api-server.

[bisgaard-itis]

FYI @wvangeit @sanderegg @pcrespov @JavierGOrdonnez @esraneufeld

After adding the celery worker to the api server I did some basic preliminary load testing of the run endpoint using locust. This doesn't test the success of the backend projects or even the celery tasks, but simply tests the api-server's responsiveness and resillience.

In this test I used 10 locust users which all hit the run function endpoint of the api-server. This test was performed on the local deployment of the platform on my work station. Here are the statistics

The reason why the endpoint can still be up to 4-5 seconds is probably because of a limited number of db connections in the webserver. But I will have to investigate this further to 100% sure.