Allow enabling/disabling sidebar per folders

[olayway]

I have a site with some landing pages, blog and docs. I want to be able to only show the sidebar in the docs.

Currently it's only possible to either enable it site-wide and disable on single pages (with frontmatter), or disable site-wide and enable on single pages. There is no way to show in all the docs, but nowhere else.

Note: this is pretty common, and we need this ourselves for Flowershow docs.

[olayway]

Giving it high priority as I wanted this already a couple of times for flowershow.app/docs (but not for blog or landing pages) and it's pretty common scenario.

[olayway]

@rufuspollock wdyt?

[rufuspollock]

@olayway i'd downvote this for now and see if it really itches us. it adds complexity and the benefit is not yet huge IMO

[olayway]

Ok, I'm gonna move it out of this milestone