Add elapsed query time to query result

[MichaCo]

Discussed in https://github.com/MichaCo/DnsClient.NET/discussions/139

^{Originally posted by jhoffmeister December 3, 2021} Hi,

I'm missing a response time in the DNSQueryResponse, I can see that the Audittrail has a response time. I can parse the Audittrail result, but it takes time to generate it, and do not give the real response time for the query.

/Jorgen