Create a new crl-storer service, which receives CRL shards via gRPC and
uploads them to an S3 bucket. It ignores AWS SDK configuration in the
usual places, in favor of configuration from our standard JSON service
config files. It ensures that the CRLs it receives parse and are signed
by the appropriate issuer before uploading them.
Integrate crl-updater with the new service. It streams bytes to the
crl-storer as it receives them from the CA, without performing any
checking at the same time. This new functionality is disabled if the
crl-updater does not have a config stanza instructing it how to connect
to the crl-storer.
Finally, add a new test component, the s3-test-srv. This acts similarly
to the existing mail-test-srv: it receives requests, stores information
about them, and exposes that information for later querying by the
integration test. The integration test uses this to ensure that a
newly-revoked certificate does show up in the next generation of CRLs
produced.
Fixes#6162
Aaron Gable