PathProcessor/Provider - separate proof queries from message assembly

[agouin]

Previously, methods such as MsgRecvPacket in the CosmosChainProvider would both query for the tendermint proof and assemble the message for the counterparty. This will only work if the counterparty is a cosmos chain. In preparation for third party chains, this separates the proof queries into the following methods:

// PacketCommitment queries for proof that a MsgTransfer has been committed on the chain.
PacketCommitment(ctx context.Context, msgTransfer PacketInfo, latest LatestBlock) (PacketProof, error)

// PacketAcknowledgement queries for proof that a MsgRecvPacket has been committed on the chain.
PacketAcknowledgement(ctx context.Context, msgRecvPacket PacketInfo, latest LatestBlock) (PacketProof, error)

// PacketReceipt queries for proof that a MsgRecvPacket has not been committed to the chain.
PacketReceipt(ctx context.Context, msgTransfer PacketInfo, latest LatestBlock) (PacketProof, error)

They all have a common signature, returning the proof as []byte and the height as clienttypes.Height ibc-go type. This information can then be passed into the message assembly function for the destination chain instead of the source chain, which can construct the message as needed for the destination chain.

[mark-rushakoff]

🚢

[mark-rushakoff]

Two function variables are fine, but at three I would probably pull out a struct or interface for this.