Diagnostics support for Thread networks.
When triaging Matter and HomeKit issues you often need to check for problems with the Thread network.
This report helps spot and rule out:
* Is the users border router visible at all?
* Is the border router actually announcing any routes? The user could have a network boundary like
VLANs or WiFi isolation that is blocking the RA packets.
* Alternatively, if user isn't on HAOS they could have accept_ra_rt_info_max_plen set incorrectly.
* Are there any bogus routes that could be interfering. If routes don't expire they can build up.
When you have 10 routes and only 2 border routers something has gone wrong.
This does not do any connectivity checks. So user could have all their border routers visible, but
some of their thread accessories can't be pinged, but it's still a thread problem.