Enable bulk run creation #853

Problem Statement

To support uploading a large number of runs, eg from a CSV file of final results or similar, we need to be able to use bulk run creation in the API.

Solution

If you provide a list of run definitions when you POST to /runs, itll create them all at once. We need some way of being able to do this.

Alternatives Considered

Just put it directly into the simvue CLI and use the sv_post function there with a list of dicts, but thats mixing upper level and lower level functionality

Additional Context

Add any other context or screenshots about the feature request here.