Upgrade P2P protobuf messages

[vbar]

Starknet specifies message formats for Tendermint consensus in https://github.com/starknet-io/starknet-p2p-specs/blob/main/p2p/proto/consensus/consensus.proto , which doesn't exist yet in pathfinder. We should replace https://github.com/eqlabs/pathfinder/tree/main/crates/p2p_proto/proto with https://github.com/starknet-io/starknet-p2p-specs/tree/main/p2p/proto and use the new structure.

[kkovaacs]

A slight update to this: currently, the actual protobuf definitions used by Starkware's implementation are not quite the same as what we have in the p2p-specs repo.

We have a promise that Starkware will publish the "final" protobufs in February in the specs repo -- we could maybe use their protobuf instead?

[vbar]

Yes - certainly the upgrade can wait until the spec stabilizes...