Merge public and secret keys and keyrings to single object(s).

[ni4]

Description

Historically we have separate secret and public keys and keyrings, with all the signatures and userids attached to both. However, secret key may be represented by the public key with additional secret key packet. Implementing this would improve memory footprint and mess with importing public/secret keys to the keyrings.

[kaie]

required for https://bugzilla.mozilla.org/show_bug.cgi?id=1857477