Backport of chunked loading and leaner pollItems

[dartcafe]

• Manual backport of Enable chunk loading polls in list and limit polls in navigation. #3479
  • chunked loading of 20 poll items
  • limit number of poll items in nav to 6
• selective manual backport of #Updating pr-feedback.yml workflow from template #3456
  • reduced transition time
  • leaner PollItem for a leaner pollList dom (better flexbox)
  • aligned navigation footer (cosmetic)

[ChristophWurst]

Code looks sane but I did not test it.

[dartcafe]

I tested it and it did what it should, but I would feel better, if I got some feedback from a beta2 test.

[st3iny]

I'm not sure if pagination works. I tried to test it locally with 27 polls and all of them are loaded right away.

In the left sidebar only 6 are shown. After clicking on Show all it loads and lists all polls.

[dartcafe]

I'm not sure if pagination works. I tried to test it locally with 27 polls and all of them are loaded right away.

In the left sidebar only 6 are shown. After clicking on Show all it loads and lists all polls.

Initially the first 40 items get loaded, because the observer is visible before the rendering of the first items is ready.