Separate binary for interacting with ibc chains

[benluelo]

TLDR - separate the relayer into a library and create a new binary on top of those types that can be used to interact with union-ibc-enabled chains in a similar way to uniond.

Rationale

uniond works great when communicating with cosmos chains, but calling evm smart contracts is much more difficult. There are dozens of CLIs and libraries for calling smart contracts, with most of them being specific to a framework or set of tooling (notably OpenZeppelin and Foundry (cast)). The main issue with these libraries and CLIs is that they work per-contract, which means that an end-user would need to know the address and abi of the smart contract they want to call, along with the semantics of said contract and its methods, in order to be able to call it.

Proposal

• Separate the chain interfaces out of the relayer (i.e. Union and Evm<C>, and their respective config types)
• Create a new binary that consumes these types, and provides a generic interface for interacting with both cosmos and evm (and any other chains we may support)
  • Move (most) existing chain-agnostic functionality out of the relayer and into this new binary (i.e. submitting packets)
• Profit

This has the added benefit of keeping the relayer small and simple - it just relays.