Download file described from DOMS

As a DOMS-GUI user I want to get the data-file that is related to the given record, so that I can check whether the metadata of the record make sense.

User story made from suggestions in sources:

DOMS-134,DOMS-143

Developer-notes:
- A user finds a record in DOMS
- He selects an object that describes a file
- He clicks the link to the file
- The file is downloaded