Code review comment for lp://qastaging/~uriboni/webbrowser-app/newtabview-listviews

> If we want to optimize for large bookmark databases, this branch doesn’t
> appear to be improving things, quite the contrary. All of this is anecdotal
> when we look at the time it takes for the application itself to launch and
> become responsive though. With 100000 bookmarks, the app takes ~20s to launch [when the new tab view is visible]

The problem was that the collapsed bookmarks view was still a Column+Repeater+Loader and that was causing the long startup. This has been solved by use of a ListView backed by a LimitProxyModel.

With this change, I can't find any major bottleneck that prevent the app to be usable in any condition.