Add advanced Azure AD OAuth/Webserver authentication example with role/group mapping

[ieunea1128]

What do you see as an issue?

The webserver-authentication.rst documentation currently shows basic authentication and some OAuth provider examples, but does not include a practical example for Azure Active Directory (Azure AD) that demonstrates how to configure Azure AD OAuth in webserver_config.py, extract roles/groups from the token, and map them to Airflow RBAC roles.
While the SSO docs include a generic Azure AD provider example, they do not cover end-to-end usage with the webserver authentication manager.

Solving the problem

Add an advanced example section in webserver-authentication.rst showing:

• Azure AD OAuth provider config in webserver_config.py
• Custom security manager subclass to parse Azure AD token claims
• Example role/group to Airflow role mapping (AUTH_ROLES_MAPPING)

This would help users using Azure AD for authentication and role mapping in real deployments.

Anything else

I opened the previous issue from the wrong account and have reposted it with the correct one. Thank you for your understanding!
#60747

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[suii2210]

I’ll work on this and submit a PR.