MailCraft crates/ews at a44a450: the request envelope and the escaping
element builder (soap.rs), and the judging of an answer's envelope, faults
and response messages (reply.rs, the response codes of error.rs), now read
with craft-xml in place of MailCraft's own XML reader. The operations, HTTP,
Autodiscover, authentication and sync stay in MailCraft.
Co-authored-by: Martin Ball <98639962+benandez@users.noreply.github.com>