Add iroh discovery of piglets on local network

[andrewdavidmackenzie]

Complete https://github.com/andrewdavidmackenzie/pigg/issues/106 with ability to discover remote Pis.

Local discovery

• Use iroh discovery for iroh-net connection.
• Use mDNS or other for discovery of IP if we have some way to connect to them (Remote GPIO?)

Remote Discovery I am not sure this is possible, but if something can be done, then add it here...

Including addition of selection to the hardware-button pop-up to initiate this, then a dialog showing progress and options to select one and initiate connecting to it.

[andrewdavidmackenzie]

Blocked by https://github.com/andrewdavidmackenzie/pigg/issues/312

[andrewdavidmackenzie]

See: https://www.iroh.computer/blog/iroh-0-26-0-Say-Hello-to-Your-Neighbors