Add Support for Multi-Factor Authentication

[fherbreteau]

Description

Mina SSH Server should have a way to handle multi-factor authentication using a generic mecanism that will be implemented as need (Google Auth, Authy, ...)

Motivation

This improvement can also improve security as required in some companies which require a private key and a security code.

Alternatives considered

No response

Additional context

No response

[tomaswolf]

Support for PKCS11 hardware security modules is not implemented in Apache MINA sshd, but could be added via the SunPKCS11 security provider. JGit did so.

Support for FIDO keys (sk_* keys) would be similar, but as there is no standard access library in Java, one would have to write one first, possibly using JNA.