ADDED: `create_desc_sign_key_cert()`
ADDED: `HsDescBuilder::hs_desc_sign_cert()`
REMOVED: `HsDescBuilder::hs_desc_sign_cert_expiry()`
BREAKING: `HsDescBuilder::blinded_id()` now takes a `HsBlindIdKey`
BREAKING: `HsDescBuilder::create2_formats()` now takes a `HandshakeType`
