Add log messages for requests, responses and errors

[robin-nitrokey]

This patch adds log messages for each request and response (and deserialization or protocol errors) in the dispatch module. This makes it easier to keep track of the executed commands by just looking at the log output from fido_authenticator::dispatch.

[robin-nitrokey]

Already reviewed as https://github.com/Nitrokey/fido-authenticator/pull/35.