request: add 2FA

[Ahwxorg]

Description:

I think it'd be a good idea to implement 2FA into Synapse and Element as a 2nd way to verify that it is really you. I know it is already suggested here: matrix-org/matrix-spec-proposals#1998, but I wanted to ask if there's any progress.

[devonh]

The current plan for user authentication in matrix is to add OIDC support via the matrix-authentication-service which implements MSC3861. Work on standalone 2FA is not currently planned in Synapse.