Move dialing to the Peer manager

[divagant-martian]

Issue Addressed

libp2p's latest release forces a quite big refactor on our lighthouse network crate mainly because of the deprecation of the NetworkBehaviourEventProcess. While doing this, I'll need to remove InternalBehaviourMessage. This PR removes one of the variants: DialPeer moving dialing from the main Behaviour to the PeerManager.

Proposed Changes

This change should maintain essentially the same over-all behaviour:
Before we would tell the peer manager to set a peer as dialing and queue an internal behaviour event to emit the Dial NBAction. The way the derive macro for NetworkBehaviour works is by polling each sub-behaviour in the order they are defined and then calling the custom poll function. Since the peer manager is the last behaviour, having the dial at the beginning of the custom poll function and at the end of the poll for the peer manager should be equivalent.

Additional Info

na

[AgeManning]

Yeah cool. We push the dialing down a layer in the PM. Seems equivalent to me.