libwebsockets

lws_conmon: connection monitoring and stats generation

This provides a build option LWS_WITH_CONMON that lets user code recover
detailed connection stats on client connections with the LCCSCF_CONMON
flag.

In addition to latencies for dns, socket connection, tls and first protocol
response where possible, it also provides the user code an unfiltered list
of DNS responses that the client received, and the peer it actually
succeded to connect to.