Revert "reverse virtuallist refactor"

[mifi]

pulled out from #5061 (do not merge before)

[github-actions]

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[aduh95]

What's the status here Mikael?

[lakesare]

The reason we have performance issues (can reproduce in 4.x too) is because we lost the functionality of VirtualList somewhere along the way. All performance issues disappear when we limit the number of rendered rows to, e.g., 100 rows (everything else stays the same - we process 10k files, etc., only the number of rendered files matters for performance).

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Proof

Here is GoogleDrive in 4.x branch, virtualList option is true, and yet 1500 items are all rendered:

Here is what it should look like instead: https://jsfiddle.net/developit/qqan9pdo.

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@mifi, would you like to debug our VirtualList implementation while you're refactoring it?

[mifi]

recreated as #5307 because i dunno what happened here. Also included your TODO @lakesare