vquic stabilization
- udp send code shared between ngtcp2 and quiche
- quiche handling of data and events improved
ngtcp2 and pytest improvements
- fixes handling of "drain" situations, discovered in scorecard
tests with the Caddy server.
- improvements in handling transfers that have already data or
are already closed to make an early return on recv
pytest
- adding caddy tests when available
scorecard improvemnts.
- using correct caddy port
- allowing tests for only httpd or caddy
Closes#10451
