client/network: Add peers to DHT only if protocols match

With https://github.com/libp2p/rust-libp2p/pull/1628 rust-libp2p allows
manually controlling which peers are inserted into the routing table.
Instead of adding each peer to the routing table automatically, insert
them only if they support the local nodes protocol id (e.g. `dot`)
retrieved via the `identify` behaviour.

For now this works around
https://github.com/libp2p/rust-libp2p/issues/1611. In the future one
might add more requirements. For example one might try to exclude
light-clients.