Collect some metrics from your zerotier

Just trying some stuff out for now

TODO

• [] integrationy tests
• [] package it up, so I can install it more easily on my devices
• [] configurable if it logs individual node addresses or not

run

go run cmd/main.go

args so far

• --web.listen-address
• --web.telemetry-path
• --zerotier.authtoken-path