Adding optional public addresses for proxying (#5807)

* Adding optional public addresses for use in network configurations to allow for proxies in front of a node.

* Apply suggestions from code review

Co-Authored-By: Cecile Tonglet <cecile.tonglet@cecton.com>

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Cecile Tonglet <cecile.tonglet@cecton.com>
Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>