This moves all verify code to an own module and adds support to check
all packet files in the structure for integrity. This is done by parsing
assumptions like packet kind, type, issuer and location etc.
This feature allows to import from a piped fd like:
> ./keyringctl import --name foobar <(gpg --export foo@bar)
We achieve this even with hidepid by taking the naive approach of
copying the processes fd source to a tempfile and pass around latter.
Currently only newly added certificates will be checked against the
expectations as existing keys are not all fully compatible with those
assumptions. New certificates are determined by using
$CI_MERGE_REQUEST_DIFF_BASE_SHA as the base,
Handle missing or wrong certificate paths in a way that does not lead to
a blocking command by reading from stdin. Instead throw either file not
found errors or expect optional outputs.
