Introduce the command which is used to change the password to
authenticate to the HSM.
A small refactoring of extracting authkey out was necessary to prevent
an import cycle from securechannel importing commands which (without the
refactor) imported secure channel again.
Documentation for this command: https://developers.yubico.com/YubiHSM2/Commands/Change_Authentication_Key.html
Add the implementation fo the DeriveEcdh command alongside a command
name that matches what Yubi calls it.
Left the previously named one alone so this doesn't break backwards
compatibility if anyone was using that.
Docs: https://developers.yubico.com/YubiHSM2/Commands/Derive_Ecdh.html