add a "Unfold all" button to the Page index of the sidebar

[redimp]

Discussed in https://github.com/redimp/otterwiki/discussions/222

^{Originally posted by schanur March 22, 2025} Hi,

is there a way to toggle folder folding on and off in the sidebar?

[rnbr04]

Hi, I am interested in working out this feature. What I have thought for now is to approach it with javascript, creating a list of nodes that have to be toggled down and giving a button to unfold them all at once

Something like this: Image Link

We can then maybe create an option in the settings page to "have" or not "have" this button.