Yubikey/U2F Key Support

[riking (Kane York)]

2fa now has a dedicated settings screen:

Second factor landing page, register multiple TOTP keys

During some flight time, I got curious about how web authentication and auth schemas worked, since I know we want to start to support it as a factor method, and started to investigate how it was implemented in certain spaces. One thing that stands out to me is that all implementations have a landing page listing out all second factor forms - our implementation of TOTP codes currently does not have this page because we had initially only offered a single second factor method. I’d like to propose…