Add missing collection UI features

[kurzum]

@holycrab13 ,
I was looking at: https://databus.dbpedia.org/dbpedia/collections/latest-core
It seems that not all dataset versions are displayed. In particular infobox-properties (not infobox-property-definitions) seems to be missing. I checked the query and the query is correct with all 82 instances.

Another thing is that we talked about these features:

• view the query in gui
• have a list of donwloadURLs (optionally with wget) in a textarea to copy them.

Furthermore it would be nice to have:

• preview (fold open)
• more detailed info on mouseover (like rdfs:comment)

[holycrab13]

I counted and all 82 sets are there, the one you are looking for is labelled
Extracted facts from Wikipedia Infoboxes (2020.04.01)
I will edit the title of the issue, since it still contains other tasks

[holycrab13]

features have been added.
I added the additional info (comment, could be more) to the fold open. Fold open is on the right side since it had to be per-file. Not sure if I found the best UI solution here.

Two additional tabs have been added to the collection public view: Query and Download URLs. They both contain a button for quick copy/paste and a text field with the respective string.

Both actions have been added to the action dropdown in the action bar at the top