Use spans of std::byte in serialize
Summary:
This switches .read() and .write() to take spans of bytes.
This is a backport of core#23438
https://github.com/bitcoin/bitcoin/pull/23438/commits/fa24493d6394b3a477535f480664c9596f18e3c5
Depends ib D15934
Test Plan:
ninja all check-all bitcoin-fuzzers bench-bitcoin
Run the seeder for a few minutes, make sure it finds nodes
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D15935