Make clearer CLI - server separation to new users

[stan-dot]

https://diamondlightsource.github.io/blueapi/main/how-to/authenticate.html
that page could contain a preface:

this is the CLI application, distinct runtime from the server application. you can have the cli application talk remotely to the server application however you need to configure both separately and make sure they have the same version

Potentially also a mention of a default podman-container-based or /scratch/{username} installation location of the blueapi cli