resolves #702 add fido2 up/uv/pin support

[schaarsc]

No description provided.

[rfjakob]

Hi, a few comments:

1. Commit message is missing (text in RFE: add fido2-with-client-pin #702 is good, put it into the commit message)
2. You cannot change existing command-line flags as this breaks existing users
3. The tests fail

[schaarsc]

I understand the wish to avoid breaking changes. In this case however, I'd advocate for it, because a) it provides a cleaner cli and b) I assume this feature is used by tech savvy people that can handle the switch from "--fido" to "--fido-device" if this is documented in the Release Notes.
to make sure already encrypted files are not affected, I left fido2(line 50) untouched in case no parameters are provided.

As for the code comments... I'm not a go developer, consider this to be a proof of concept, in my opinion a skilled developer should take it from here and make the appropriate changes / quality checks required for this project.

[rfjakob]

Functionality will be merged via the simpler #807