Lazy load panels below the fold

[ycombinator]

For really large dashboards (i.e. dashboards with a lot of panels in lots of rows), it would be nice if the panels below the fold (or below the fold + 1 row) would be lazy loaded upon scrolling.

[stacey-gammon]

Closing in favor of the more generic #14750

Streaming result data back could help with this if we prioritized data on the screen, but improving dashboard performance needs to be thought of as a whole.

Also, doing anything like this would require a massive courier refactor. Something we should do anyway, but since this is not a simple feature, and dashboard performance as a whole needs to be improved, I think it makes sense to consolidate all ideas in that one ticket.