Auth without using FlowFuse

### Description

Hi team FlowFuse!

Congrats on the recent release and on the awesome demo of multi-user dashboards!

In light of that I have a request: could we allow an auth workflow for dashboard on standard OSS Node-Red? I love using FlowFuse, don't get me wrong, but I teach at tradeshows where I don't have a reliable internet connection. I could perhaps self-host FlowFuse and run it on prem, and I'm open to that, but I'd also just love to be able to use a simple local auth flow.

This could be basic auth...storing the username & password as a cookie and passing them via headers on every request. This could also be something more like a session token / JWT...where the user authenticates, a flow validates the auth, then sends a JWT as a cookie back to the user...then every subsequent request from that client would include additional session & user id information in the ._client object.

I'm not particularly picky how...but I do need a unique way to authenticate & keep track of a unique user. It does seem that this could be done with a dashboard-2 plugin...and I'm also open to working on that if we feel that's the right approach. But I wanted to ask first if this should be native functionality in the opinion of the maintainers.

Then again, you tell me: if I can do this with self-hosted FlowFuse, I'll look to do that for now.

Thanks!!

### Have you provided an initial effort estimate for this issue?

I am no FlowFuse team member