Setup Local Interchain integration test environment

[stiiifff]

Setup a Local Interchain integration test environment in the repo to test IBC-related functionalities. Local Interchain seems to be an interesting approach, compared to Interchain Test, for the following reasons:

• Tests can be written in Rust instead of Go
• CI setup is simpler, with a single setup step (configures the IBC network) followed by a number of tests that run on that network.

Example implementation: https://github.com/Reecepbcups/interchaintest-rust-example

[stiiifff]

Closing, as it's a duplicate of #238.