Proposal Details

Basically, https://go-review.googlesource.com/c/crypto/+/681037 because it helps understand the issues the ACME server encountered with the order when that errors.

It also better implements RFC 8555 by making this more accessible and easier to introspect as well since all errors from an ACME compliant server should have a problem description which an Error already helps describe and which we lose from an OrderError.