move discv5 to structured logging

[divagant-martian]

transform logging statements from using formating in strings to structured logging, for example:

- debug!("Node set to disconnected: {}", node_id)
+ debug!(%node_id, "Node set to disconnected")

This would make it easier to make sense of emitted logs

[emhane]

it should be possible to shorten lists of node ids with

format!("[{:#}]", list.iter().format(", "))

https://github.com/paradigmxyz/reth/issues/6080#issuecomment-1893329173