Support a PGP key ID in control.ctl

[eagle]

Resolve the problem with ambiguous key IDs by specifying a PGP key ID in control.ctl instead. The easiest way to do this is by adding a new keyword instead of verify- (pgpid-, perhaps) which takes a key ID instead of an ID and is otherwise the same. Alternately, one could look at whether the verify- argument looks like hex.

[Julien ÉLIE]

Though support for PGP key IDs could be added in control.ctl, please note that the motivation for that enhancement is fixed in INN 2.5.4 (commit [9621]).
It was originally for dealing with several UIDs on a single PGP key, as well as spaces in UIDs.

[Julien ÉLIE]

Beware that it is possible that a few PGP implementations do not return the key ID.

PGP 5.0 also returns 4 bytes instead of the complete key ID, containing 8 bytes (F985E3400AFC7476).

# PGP 5.0:
# Good signature made 1999-02-10 03:29 GMT by key:
# 1024 bits, Key ID 0AFC7476, Created 1999-02-10