David Runge authored Oct 18, 2021 and Levente Polyak committed Nov 30, 2021

keyringctl:
Add `get_fingerprints_from_import_source()` to derive all fingerprints
of PGP public keys found in the import source.
Add `get_fingerprints_from_decomposed_dir()` to derive all fingerprints
of PGP public keys found in a directory structure holding decomposed PGP
packet data.
Add `get_fingerprints()` to derive a set of fingerprints of PGP public
keys provided through `get_fingerprints_from_import_source()` and
`get_fingerprints_from_decomposed_dir()`.
Change `convert()` and `convert_certificate()` to accept an optional set
of strings (`fingerprint_filter`) that may be used as a filter for
valid fingerprints when considering certifications.
Change `__main__` to call `convert()` when importing keys to packager or
main dir, providing `fingerprint_filter` which will attempt to look up
fingerprints in the source as well as the target.