Fix corrupt retrans2

Fix null deref in H3 request format

Make sure that retransmissions do not exceed the coalesced packet size.

Fix the "usage" menu in picoquicdemo

Fix huffman decoding bug in request headers

Ignore initial frame with short CID

Fix usage of tokens, tickets

Set CC algo to Cubic in demo

Checks status oof MAX DATA frames, etc, before retransmit

Verify HTTP3 interop with ATS. Fix QPACK decoding. Add "authority" he…

Fix server preferred address

Align with latest version of TLS, update key logging procedure

Reproduce demoted cnxid bug in updated test and fix.

During interop tests, Lars observed a scenario in which after picoquic sends a `RETIRE_CONNECTION_ID` frame for seq 0, it keeps sending packets to that DCID. This was the "renew CID" scenario. The bug only occurs if the test lasts long enough to trigger the deletion of "demoted" paths. The PR fixes the unit test so this bug can be detected, and of course fixes the bug.

CID encryption Example