Resolve "datasetparameter endpoint : add dataset type filter"

Closes #500 (closed)

This will allow to optimize data-portal!310 (merged) as it needs to fetch the list of available scanTypes for raw data only, which currently requires two requests:

• One request to get the whole list of scanTypes (raw and processed)
• Another request to get the list of input_datasetIds parameter to filter out the processed datasets from the previous call (if they have input_datasetIds then they must be processed)

This simplifies it by adding datasetType parameter : /datasetparameter?investigationId=124404803&name=scanType&datasetType=acquisition will do it in a single request.