Option in vscode extension to collapse all distribution plots by default

[joel-becker]

For BOTECs with many components, it gets annoying to collapse ~all plots each time I re-open. Maybe I'm doing something wrong!

[OAGr]

It's a good point. Right now, on the Squiggle Hub, we automatically close all nodes if there are over 20 nodes or so. We're working on figuring out better heuristics here.

[OAGr]

Btw, recent changes have led to many more items being collapsed. I think good defaults are the first thing to get right.

Let me know if this still isn't enough. I could see making things more configurable, but it would be more work. Tags could be a nice solution here.