Feature addition: TLSRPT

In line with the new contributions policy, would there be interest in
adding support for TLSRPT https://www.rfc-editor.org/rfc/rfc8460 ?

RFC8460 describes a reporting mechanism and format by which sending 
systems can share statistics and specific information about potential
failures with TLS connections to recipient domains.  Recipient domains 
can then use this information to both detect potential attacks and
diagnose unintentional misconfigurations.

I would be using the library
     https://github.com/sys4/libtlsrpt/
which connects to a service provided by
     https://github.com/sys4/tls-reporter/

Postfix has used these to provide TLSRPT for over a year, though this is 
not currently enabled in Ubuntu - I don't know about other distros.

Ideally a small amount of MTA-STS would be used but I am not sure that
that would have to be within exim rather than the tls-reporter 
service.

-- 
Andrew C. Aitchison                      Kendal, UK
                    [email protected]

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