Composite private key encoding

[ounsworth]

From the mailing list:

https://mailarchive.ietf.org/arch/msg/spasm/04czobwhAH7Z0iLx00Ow4Y9MaHY/

have a sequence of octet string representing
the private key octet strings as they would appear in the single key
PrivateKeyInfo object.

This is what we intended to do in the IETF 122 drafts, but we missed updating the private key text. The format would be:

CompositePrivateKey ::= OCTET STRING
where that OCTET STRING is
len(pqkey) || pqkey || tradkey
and the pqkey, trad key are as they would appear in a single-key PrivateKeyInfo.privateKey or OneAsymmetricKey.privateKey.