Simplify requirements display, fix duplicated hands-on

[hexylena]

xref #4956

Screenshot	Comments
	The current display. Users probably do not need to go to the topic, they're being directed to a specific tutorial, the topic link is a bit of a red herring. There is not much 'paint' for the small buttons. Are both materials mandatory? Unknown!
	New display, every material listed sequentially. Considered prefixing all with "Single Cell / ..." but this was very redundant and not interesting or useful I think?
	Now slides + hands on are listed sequentially showing that you should follow these in this order.
	makes me think we need a topic icon.