Update libp2p to v0.3 (#1634)

* Update libp2p

* Some more diagnostics

* 30 seconds back to 5 seconds

* Bump libp2p-core and improve test

* Fix runtime Cargo.lock

* More work

* Finish upgrade to libp2p 0.3

* Add a maximum of 60 seconds for the rounds

* Remove env_logger

* Update Cargo.lock

* Update Cargo.lock in test-runtime

* Fix test compilation

* Make the test pass

* Add identify addresses to Kademlia

* Don't connect to nodes we're already connected to

* Add warning for non-Substrate nodes

* Fix external address not added

* Start in Enabled mode