More extensions

[msirringhaus]

1. Credential protection policy:
   a) Stop exposing ctap_types in our API and use our own implementation for the webauthn-layer (the CTAP layer still uses ctap_types)
   b) Also support enforce_policy, which we can only do from the inside, as we need Ctap2GetInfoResponse for that. Error out, if it can't be enforced.

2. Support credProps extension.
   a) Pretty straight forward, except that CTAP 2.0 devices are allowed to create discoverable credentials even if they are not requested. CTAP 2.1 devices are not allowed to do that anymore. So we need Ctap2GetInfoResponse once again to decide

3. Switch from LargeBlobKeys extension to LargeBlob extension.
   a) LargeBlob extension has "Preferred"-mode as well, so we need Ctap2GetInfoResponse again for deciding, if we can request it or not.
   b) LargeBlobKey-requests can easily be mapped into LargeBlob requests, by simply using LargeBlob support = "required", so I'm not supporting both in the API.
   c) GetAssertionLargeBlobExtension::Write() is not yet supported, as we need the corresponding CTAP commands to store large blobs for that, which we don't have yet.

[AlfioEmanueleFresta]

Thank you!