Support for parsing smartcard/HSM related fields (mode 1002, gnu-divert-to-card S2K)

The patch allows parsing SecretKeyPacket and SecretSubkeyPacket that are tied to smartcard reader.

Sample keyfile generated by gpg --export-secret-key is [here](https://github.com/hiviah/python-pgpdump/blob/smartcard_s2k_key_sample/B2222939-priv.bin).