refactor: Simplify bitswap `WantSession`

[dariusc93]

This PR simplifies some parts of bitswap WantSession by:

• Using a single field to manage of the peers local state
  • We use IndexMap so we can track the order of the peer and act accordingly.
• Change discovery to an enum to track when to use a timer to emit a NeedBlock based on specific conditions
• Pass on and track previous peer id when a request fails.

Additionally, we will only track the connection id as the behaviour would have no need to track the addresses themselves.