EPIC: Hyperlane relayer - Cosmos SDK module support

[misko9]

Allow a hyperlane relayer to be able to sign and broadcast hyperlane.mailbox.v1.MsgProcess transactions

Tasks

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1. Add cosmos RPC support / configuration to hyperlane relayer #46
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2. Add cosmos keychain support to hyperlane relayer
3. Add cosmos transaction serialization support to hyperlane relayer
4. Add cosmos transaction signing support to hyperlane relayer
5. Add cosmos transaction broadcast logic to hyperlane relayer
6. E2E test: interchaintest: Cosmos <-> Cosmos data transfer #47
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7. Relayer: Investigate existing interfaces/traits #55
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Implementation will follow what's being stubbed here:
https://github.com/hyperlane-xyz/hyperlane-monorepo/pull/2466/files

[jonathanpberger]

@KyleMoser pls review this list; are these pieces of work they still the plan? If so, let's create real GH Stories for 'em. @DavidNix is interested, you may wanna pull him into the conversation.

[yorhodes]

much of this is scoped already here hyperlane-xyz/hyperlane-monorepo#2421

[misko9]

Implementation is ready to begin testing. Validator announce will be first to test so that a relayer can get storage locations. Then, e2e testing with validator and relayer agents together. After that, interchain gas paymaster support will be added.

[jonathanpberger]

Changed strategy, redeployed contracts. Closing ticket.