Implement mock cosmos chain using ibc-rs, tendermint-rs and basecoin libs

[Farhad-Shabani]

Closes: informalsystems/hermes-sdk#24

Context

Given improvements made to basecoin-rs (turning it into a library and moving the store types and implementations into a separate crate from the application part), It became possible to implement a mock cosmos chain.

• Concerning the consensus engine, a simple block production engine has been used. Without needing to go through the entire voting, validation, transaction, etc. processes that a CometBFT engine requires. This is achieved using the tendermint-rs crates (specifically tendermint-testgen).

• As for the application itself, the necessary modules (Authentication, Bank, and IBC) have been imported from the basecoin_app crate. This has resulted in a fully operational ibc-rs that can be run in a lightweight in-memory manner.

• In terms of the store part, the benefit of the in-memory AVL store implementation within basecoin_store can now be realized, which enables proof verification.

• Within this PR, tests for creating and updating clients are included, and further tests can be added perhaps in separate PRs.

This implementation can serve as a foundation for developing a new mock module in ibc-rs. Additionally, it can be leveraged as an exemplary implementation for the ongoing development of the ibc-rs doc portal.

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PR author checklist:

• Added changelog entry, using unclog.
• Added tests: integration (for Hermes) or unit/mock tests (for modules).
• Linked to GitHub issue.
• Updated code comments and documentation (e.g., docs/).
• Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• Reviewed Files changed in the GitHub PR explorer.
• Manually tested (in case integration/unit/mock tests are absent).

[soareschen]

This PR has been moved to informalsystems/hermes-sdk#40