This is needed for events such as recovery:loss_timer_updated, which
contain the timer expiration timestamp encoded as a difference from the
event time.
* qlog: implement a Trace and a Writer struct
* qlog: rename Trace to FileSeq
* split qlog trace writer and QUIC qlog events into separate packages
* use the new qlog.Recorder instead of the logging.ConnectionTracer
* qlog: use fork of encoding/json/jsontext instead of unmaintained gojay
* implement a minimal jsontext-compatible encoder
* qlogtext: improve fuzz test
* qlog: simplify JSON encoding error handling
* qlog: make use of jsontext.Bool
