docs: non-docker based deployment guides

[namliz]

The Quickstart was useful to play around with but I think it might give the wrong idea: SSO is not actually coupled with docker or k8s.

It also works great with old fashioned unit files. If there's any interest I'd be happy to improve the docs in that regard.

[shrayolacrayon]

Thank you for opening this issue @zilman. We would be interested and appreciate any contributions to improving the documentation!