Use a lookup key based on the container request to find containers to be reused

[mdelapenya]

    > The fix makes sense from a technical perspective. However, regarding the `reuse` behavior itself, we decided in `testcontainers-java` that relying on the container name is not a stable indicator of equality(with the name itself potentially leading to conflicts) and we, therefore, use the hash of the container create command as the lookup key.

@kiview what do you think if we proceed with the merge, and create a discussion/issue to refactor how the reuse container feature works: if I understood correctly, a container should be reused if and only if the container request (Go abstraction) is exactly the same, identified by a unique hash of the struct representing the request.

Originally posted by @mdelapenya in #558 (comment)