Multi node integration tests

[julienrbrt]

We have currently 3 integrations tests (https://github.com/rollkit/go-execution-abci/tree/main/.github/workflows):

• Liveness (integration_test.yml)
• IBC (integration_test.yml)
• Cosmos SDK tp Rollkit Migration (migration_test.yml)

Those 3 integrations tests are relying on a single node chain, which is sufficient for now.
Eventually we should update them to use a 2-4 nodes setup, to make sure everything runs smoothly.

[julienrbrt]

Multi-node integration tests should be done using Tastora (ask help from @chatton if needed) instead of extending our current workflows.