ip_address in Config shouuld be the broadcast address for the LAN, not the IP address of the host.

Posting this on behalf of Rick Burke - See [New Alpaca driver not being discovered #9501](https://ascomtalk.groups.io/g/Developer/message/9501). Also correct the comments to talk about receiving not sending broadcasts. This needs to be covered in the docs and also the docstrings for  the DiscoveryResponder class. 