Add additional grpc queries for channel/v2

[DimitrisJim]

Looking at the ones existing for v1 and what we use in v2, these should probably be implemented (feel free to edit otherwise!):

• PacketCommitment chore: add v2 packet commitment query #7494
• PacketCommitments feat: add paginated packet commitments query to channel/v2 #7533
• NextSequenceSend chore: add next sequence send query. #7550
• PacketReceipt chore: impl packet receipt query #7513
• PacketAcknowledgement chore: impl packet acknowledgement query #7507
• PacketAcknowledgements chore: add packet acknowledgements rpc #7558
• UnreceivedPackets chore: add unreceived packets rpc #7561
• UnreceivedAcks chore: add unreceived acks rpc #7562
• Channels chore: add channels rpc #7560

All these already exist in query.proto/grpc_query.go for v1 channels. Moving them over should be relatively straight forward.

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[damiannolan]

I'll start by adding PacketCommitment / PacketCommitments in an isolated PR.

[DimitrisJim]

Will add NextSequenceSend myself

[DimitrisJim]

Will pick up PacketAcknowledgements on the morrow

[DimitrisJim]

need to also add Channels rpc.