BLOCKER: Investigation type and ebi per preprocessed

This adds the possibility of setting investigation types and then submitting those to ebi.
This exception should perhaps suggest to the user that if the `investigation_type` is not a know term, the user should use `Other` and provide a `new_investigation_type`. Not sure how applicable this is as we are not currently exposing this functionality to the end user through the GUI so it's up to you to add it or not.