Save/download full result of query

[aswallace]

Use Case

Allow users to save the full result of a query (the metadata, not the files themselves) as a csv (or other file type).
I can't remember who requested this or if we'd already decided not to do it, please feel free to edit/close the ticket if you do remember.

Suggest a Solution

Add a "Save metadata as..." or "Save result of query as..." button to the icons in the query toolbar (in the footer of screenshot)

Additional Details

This is related to #410 but more limited in scope -- would save the metadata for all files from the query, but wouldn't actually select the files, so prevents users from doing things like editing all the metadata or moving all the files to NAS

Potential issues: We may not want to allow this when no filters are applied, since we have millions of rows of files in FMS.