Add B2C authentication

[zedhaque]

Please provide us with the following information:

This issue is for a: (mark with an x)

- [ ] bug report -> please search issues before submitting
- [X] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)

Expected/desired behavior

Add support for B2C authentication particularly multiple social login. Furthermore it will be great if we can display multiple social login icons as well as ability to modify branding in the login/logout page or pop-up. I have a site where I like to implement this before hackathon ends :)

[pamelafox]

cc @mattgotteiner @jamesc

[pamelafox]

Here's a PR from @jamesc that added B2C authentication to a simpler (non-RAG) chat sample:

https://github.com/Azure-Samples/openai-chat-app-quickstart/pull/54

We'd need to identify what is missing from this repo that's in that PR. I think Matt and James have discussed the differences in the past. I have not yet had the time to review that code carefully myself.

[mattgotteiner]

Thanks for the feedback during our session. Yes, we can take on this task

[mirojs]

@mattgotteiner Hello, should we expect this feature to come up soon? Thanks.

[mirojs]

@pamelafox May I know if this one is still ongoing? Thanks.