Fix: Use netutil to check UDP ports instead of discover's ping (#160)

* fix: use netutil to check UDP connection

* Make ping private

* use public address from local

* add missing import

* update hive.go version

* repeat sends directly in protocol

* retry ping to ensure verified

* Apply suggestions from code review

Co-Authored-By: Luca Moser <moser.luca@gmail.com>

Co-authored-by: Luca Moser <moser.luca@gmail.com>