fix: require confirmation of global unicast addresses

[achingbrain]

Some routers will allocate global unicast addresses which peers will treat as publicly routable. The routers may also firewall any incoming traffic to these addresses so require confirmation that the node is reachable before publishing such addresses.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works