By default, each certificate is now output only once per hour. This also
should work in cluster mode, where we use the net broker-table-syncing
feature to distribute the information about already seen certificates
across the entire cluster.
Log caching is also pretty configureable and can be changed using a
range of confiuration options and hooks.
Note that this is currently completely separate from X509 events
caching, which prevents duplicate parsing of X509 certificates.
In the past I thought that this is not super interesting. However, it
turns out that this can actually contain a slew of interresting
information - like operating systems querying for the revocation of
software signing certificates, e.g.
So - let's just enable this as a default log for the future.
