Update OpenPGP key support to v6 (including PQC)

[dralley]

Is your feature request related to a problem? Please describe.

Support for an OpenPGP keyring repository was added in #5133 for RFE #3024

That includes a fair amount of PGP key parsing code.

That parsing code needs to be update to support V6 signatures, including any support for PQC algorithms.

Additional Context:

https://redhat.atlassian.net/browse/PULP-1353

[mdellweg]

I believe this is the document to look at:

https://datatracker.ietf.org/doc/html/draft-koch-librepgp

[dralley]

It's not actually, LibrePGP is the "fork" of the OpenPGP standard led by the maintainer of GPG