Use `<details>` on large listings?

[ShadowJonathan]

When working on #294 (in #376), and live-testing it in the management room, I got a comment that the listings simply were way too big, and that hiding the text would be useful.

There is an HTML tag called <details> that would allow this, the Element Web client already supporting rendering of this;

However, a quick look at the Element iOS client shows that it doesn't support it, and I don't know about Element Android.

This'd probably be nice in combination with the solution in #376, allowing users to hide massive walls of text but also quickly go to a specific subset of information in that large amount of text. (By just clicking the arrow next to the relevant header)

[turt2live]

This issue isn't actionable because it doesn't describe what it would affect other than "lots of text". The root issue here is #129 - we should keep conversation there.