* feat(log): log the state tip height as part of sync progress logs
* fix(log): downgrade some verbose state logs to debug
* feat(log): log successful gossiped block verification at info level
These logs help us diagnose slow progress near the tip.
There won't be very many of these logs,
because they only happen near the tip.
* fix(log): spawn top-level tasks within the global Zebra tracing span
* fix(log): spawn blocking top-level tasks within the global Zebra tracing span
Co-authored-by: teor <teor@riseup.net>
Alfredo Garcia
Jane Lusby
Henry de Valence