Check that we can log version mismatch errors appropriately

[rmarx]

As noted in #138 (comment), version mismatch problems causing a connection close are logged in 3 ways currently:

1. with a version_mismatch trigger value in connection_closed
2. by logging the on the wire versions in packet_sent and packet_received .supported_versions
3. by emitting a separate version_information event grouping both external and internal (see below)

TransportVersionInformation = {
    ? server_versions: [+ QuicVersion]
    ? client_versions: [+ QuicVersion]
    ? chosen_version: QuicVersion
}

This feels clunky, but probably gets the job done, with 1 proposed change:
Currently QuicVersion is defined as : hexstring and I would define it as : hexstring / "none" to support the mismatch case explicitly in that event as well (currently you'd omit the chosen_version field to signal the same).

Another change we could do is to add ? supported_versions: [+ QuicVersion] to the server_listening event to make it more explicit which versions a server supports at startup (currently no real way to indicate that). Not sure this is crucial though.

---

One of the main points however is that I'm not sure this:

1. allows logging of all the possible flows with the VersionNegotiation extension . Maybe someone who's implemented that logic can give some insight? CC @huitema

2. should even be an issue for the qlog documents (as we're leaning towards having separate qlog documents for separate QUIC features/extensions). CC @LPardue

[LPardue]

We closed the PR that was linked to this (#138) so can we just close the issue?