Upgrade libp2p to 0.49.0 (#12256)

* cargo upgrade libp2p

* Get rid of `NetworkBehaviourEventProcess` in handling of `CustomMessageOutcome`

* Get rid of `NetworkBehaviourEventProcess` in handling of `request_responses::Event`

* Get rid of `NetworkBehaviourEventProcess` in handling of `peer_info::PeerInfoEvent`

* Get rid of `NetworkBehaviourEventProcess` in handling of `DiscoveryOut`

* Get rid of `poll()` method in `Bahaviour`

* minor: comments

* Upgrade libp2p to 0.49.0 (unreleased)

* Support multiple Kad protocol names

* Make borrow checker happy

* minor: wording

* Make substrate build with libp2p-0.49.0

* rustfmt

* Get rid of MdnsWrapper

* Resolve deprecation warnings

* Fix documentation

* Apply suggestions from code review: fix typos

Co-authored-by: Aaro Altonen <[email protected]>

* Apply suggestion: simplify kad protocol name matching

Co-authored-by: Aaro Altonen <[email protected]>