[Feature Request]: Allow users to enter API keys

[arcuru]

This is something I originally wanted to do, but I'm still not sure if this is a great idea.

The idea would be to allow someone to setup a server, and to let a user on Matrix alone start a Room with Chaz and provide their own API key or their own endpoint.

This would allow me to setup a single public "Chaz" instance, and let anyone use it with their keys.

Obviously, this needs to come with some kind of Notice/Disclaimer about the keys. Keys can be stored entirely inside Matrix (room tags) so we don't store anything local, however the user does need to trust that the Chaz instance they're using won't be running a modified version that steals API keys. And that the Chaz instance doesn't get compromised.