Support restricting token type

[icb-]

Please add support for the type parameter for token verification (application_tokentype feature of privacyIDEA). In particular, I want to be able to restrict users to webauthn tokens, even if they have another token type (e.g. totp) enrolled.

I can partially work around this with an IP address condition on an authorization policy to select allowed token types, but this means other verification checks from the same IP addresses (e.g. with the PAM module) also have the same set of allowed token types.