Create cw-multi-test IBC tests for the wormchain-ibc-receiver contract

[kakucodes]

IBC functionality can be tested for in the cw v1.5 cw-multi-test. Technically we will utilize abstract-cw-multi-test which is a fork of mainline cw-multi-test which has implemented the logic of ibc under the hood.

These changes should not really go upstream until the wasmd upgrade for gateway is also merged in and ideally we'd have a sibling pr that upgrades all of the contracts to utilize cw1.5.

[jtieri]

It would be best to get Joel's changes merged for upgrading the chain deps, specifically the CosmWasm version, then the contracts can be upgrade afterwards and those changes can be deployed separately.