Create GitHub Pages for docs.

[pree]

I think it would be nice to have the docs presented in GitHub pages.
Alternatively (once donated) we can add the docs to openbao.org?

[eyenx]

Idea is to donate to github.com/openbao, integrate it also into a the official helm chart and add the docs there.

[pree]

Works for me, let's keep the issue open to track it