Relayer CLIs for channel close messages

[ancazamfir]

Crate

ibc, relayer, relayer-cli

Summary

MsgChannelCloseInit and MsgChannelCloseConfirm raw messages are defined here:

https://github.com/informalsystems/ibc-rs/blob/1a77c0af20dee97d45096c4bcafe189c6a4f7689/proto/src/prost/ibc.core.channel.v1.rs#L276-L386

Required:

• domain type message definition + implementation
• relayer CLI to trigger the channel close
• relayer CLI to query for channel close and finish the close handshake
• update in the relayer v-0 CLI loop to register for close events and exit

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