[backport#14060] ZMQ: add options to configure outbound message high water mark, aka SNDHWM

Summary:
a4edb168b635b6f5c36324e44961cd42cf9bbbaa ZMQ: add options to configure outbound message high water mark, aka SNDHWM (mruddy)

Pull request description:

ZMQ: add options to configure outbound message high water mark, aka SNDHWM

This is my attempt at https://github.com/bitcoin/bitcoin/pull/13315

Backport of Core PR14060 https://github.com/bitcoin/bitcoin/pull/14060/commits/a4edb168b635b6f5c36324e44961cd42cf9bbbaa

Test Plan:

ninja check
test_runner.py interface_zmq

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D6473