Feature - Validate scripts

Description

When creating an assignment, it can be easy create a script that won't work on the actual submissions. Therefore the user's scripts should quickly be checked on submitting an assignment to make sure they will work on the real data.

Priority - Medium

It would be very nice to have and avoid problems with assignments but it is not of the greatest priority now.

Definition of done

• Added an endpoint to test a script for a specific metric
• View the script validation results in the UI
• Validate all scripts whenever an assignment is edited
• Refactor report generator to include errors in results