[Dokka] Better support for versioned docs

[cmelchior]

It seems that Dokka already has a concept for providing versioned docs with a better UX which would also solve the problem with the version being part of the URL: https://kotlin.github.io/dokka/1.5.0/user_guide/versioning/versioning/

We should investigate if this could replace our current approach where we put docs in this structure:

/0.2.0/
/0.3.0/
/0.4.0/
/latest/

See Kotlin/dokka#2022

/cc @nathan-contino-mongo

[nathan-contino-mongo]

I think this makes a lot of sense since it's a Dokka feature -- I can't tell from the linked docs, but I assume this plugin creates a version selector on each page that the user can choose from? Seems like a pretty minimal change from our perspective, so let's give it a shot.

CCing @cbush since this might have some consequences for YokedOx going forward.