[Cedar Doc Issue] Versioned docs

[mwhicks1]

What were you trying to do?

View the docs for Cedar 2.4.x

What is wrong and why?

I can't. The docs are for the latest version of Cedar. Therefore, if I am running an older version (or the Cedar playground is), I can't tell exactly what is supported and what isn't.

What do we need to do to fix this?

Make versions of the documents that are tied to version. For example:

• Create a Git version branch for older doc versions so at the least the raw source can be built
• Build older versions for the docs.cedarpolicy.com site and link them from some sort of table of contents. Always do this for the version running on the Cedar playground, but perhaps do it for other versions too