Add ability to verify Yubikey second factor, list second factors

Dep: https://github.com/SURFnet/Stepup-Middleware-clientbundle/pull/4

The identity ID is currently hard-coded to `45fb401a-22b6-4829-9495-08b9610c18d4`. This identity must be present in the middleware.

- [x] Translate translation keys
- [x] Change back to client@dev-develop
Then as a controller it is my concern that I'm indeed dealing with an Identity imo. I could remove the `instanceof FooToken` check, but the controller action won't work if the User is not an Identity.