[DSpace 8 Admin Reports] Allow Metadata Query report results to be exported in CSV format.

[pilasou]

DSpace 8 Metadata Query report results are only displayed in the UI. Users cannot export the results. 

A way to add an export option would be to mimic what already exist in DSpace for batch metadata import/export using one of the following scripts:

• Metadata export https://github.com/DSpace/RestContract/blob/main/scripts/metadata-export.md
• or metadata export search: https://github.com/DSpace/RestContract/blob/main/scripts/metadata-export-search.md

Content Reports could be a special type of "Scripts & Processes" like export metadata and, in the implementation, content report results should be stored as bitstreams and the best part of this is that, currently, we already have an User Interface to deal with Scripts and Processes and file downloads.