Feature Request: It would be convenient to be able to deploy multiple versions simultaneously

[arika0093]

First of all, thank you for providing such a wonderful library. It is very helpful to be able to deploy easily!

The content of the request is to host multiple versions in the following folder structure simultaneously.

- 0.1.0 (such as version number)
  - index.html
  - *.dll
- 0.2.0
  - index.html
  - *.dll
- 0.3.0-preview.1 (folder name can be freely decided)
  - index.html
  - *.dll
- 0.3.0-pr123 (for example, generating a preview for each PR)
  - index.html
  - *.dll
- latest -> 0.2.0 (optional; symbolic link)
- develop -> 0.3.0-preview.1 (optional; symbolic link)
- index.html (redirect to latest/index.html)

If this structure is supported, for example, it would be very convenient to keep documentation for each version of the library or generate previews for each pull request.

Currently, it seems possible to handle this forcibly using GHPagesBase, but the symbolic links mentioned above are missing and it requires specifying full paths.

Reference: The mike plugin for mkdocs achieves something similar.
https://github.com/jimporter/mike

I would appreciate your consideration.