[Feature Request] Support Mudlet's new telnet GMCP auth

[Griatch]

Is your feature request related to a problem? Please describe.

https://wiki.mudlet.org/w/Standards:GMCP_Authentication

This describes a telnet-GMCP-centric authetication mechanism, suitable both for username/password and oauth. It would be interesting to support in Evennia, especially if Evennia adds oauth support for web logins.

Describe the solution you'd like

Research would need to be done for extending the GMCP protocol in evennia/server/portal/telnet_oob.py to support authentication like this. Most likely evennia/server/inputfuncs.py as well. See the ingoing message path in the Evennia docs for more info.

There are two settings here, password-credentials and oauth. Since we don't yet have oauth for web logins, the password login would be the simpler case here, and something to start with.

Describe alternatives you've considered

Additional context

[vadi2]

For inspiration, an implementation inspiration in Python can be found here - it's really small: https://github.com/vadi2/gmcp-auth-mock/blob/main/mock.py#L53-L77