Hardware token: Initial support (static password)

[perry-mitchell]

Yubikeys, for example, have support for static passwords via their configurations.. Which would be an acceptable first step for supporting multi-factor offline authentication.

For those wondering, we can't use standard Yubikey authentication as it requires a remote service for validation.. which we don't have for vaults in general.

This would depend on MFA for vaults in the core, first.