Add community-extension: MFA Plugin Collection

[melegiul]

Hello Keycloak Team,

Our organization would like to share a collection of MFA extensions with the Keycloak community. We're excited to contribute and would appreciate any feedback you may have.

The project includes three extensions:

• SMS Authenticator: An implementation of the Authenticator SPI for SMS-based MFA, inspired by dasniko’s 2FA SMS authenticator.
• Enforce MFA Authenticator: Supports the scenario where users authenticate with a second factor. If neither is available, the user can choose to register one. Based on this Keycloak PR.
• Native App MFA Integration: Enables a dedicated mobile app as an MFA method, inspired by the Action Token Authenticator example.

We would be thrilled to have our extensions included in the official Keycloak extensions listing. Thank you for considering this!

[ahus1]

Thank you for sharing these extensions! I see they also have docs on how to use them, which is always appreciated!