Simplify the WFE `RevokeCertificate` API method in three ways:
- Remove most of the logic checking if the requester is authorized to
revoke the certificate in question (based on who is making the
request, what authorizations they have, and what reason they're
requesting). That checking is now done by the RA. Instead, simply
verify that the JWS is authenticated.
- Remove the hard-to-read `authorizedToRevoke` callbacks, and make the
`revokeCertBySubscriberKey` (nee `revokeCertByKeyID`) and
`revokeCertByCertKey` (nee `revokeCertByJWK`) helpers much more
straight-line in their execution logic.
- Call the RA's new `RevokeCertByApplicant` and `RevokeCertByKey` gRPC
methods, rather than the deprecated `RevokeCertificateWithReg`.
This change, without any flag flips, should be invisible to the
end-user. It will slightly change some of our log message formats.
However, by now relying on the new RA gRPC revocation methods, this
change allows us to change our revocation policies by enabling the
`AllowDoubleRevocation` and `MozRevocationReasons` feature flags, which
affect the behavior of those new helpers.
Fixes#5936
dab8a71b0e