Change name of folder that contains HTML outputs

[zkamvar]

Right now, we've adopted the {pkgdown} convention of naming the output folder "docs" because we initially thought about setting up the lesson potentially as an R package that could be shared (e.g. for learner materials).

Since we have not yet reached that point/have deviated from the design and some users have noted that it's confusing for the HTML files to be in a folder called 'doc', it would make more sense for us to change the folder name from site/docs/ to something like site/pub/ or site/deploy/.

[bencomp]

It's not too big of an issue to me, but when I sandpaper::build_lesson() locally, like just now, I first think "the HTML must be in built" before remembering that it's in docs. (If you want to push the Carpentry terms and you first say it was built, the end result should be in something like sanded, or indeed varnished. 🤓 )

[zkamvar]

I first think "the HTML must be in built" before remembering that it's in docs.

That's definitely a sure sign that we have a norman door there. 🤔 This might actually be a good candidate for a mid-field issue for the @carpentries/workbench-maintainers since it's not really a public-facing folder.