Integration test can only be executed on microk8s

[misohu]

From the code in integration tests is clear that the test will only pass on microk8s environment e.g.:

async def does_minio_bucket_exist(bucket_name, ops_test: OpsTest):
    """Connects to the minio server and checks if a bucket exists, checking if a bucket exists.
    Returns:
        Tuple of the return code, stdout, and stderr
    """
    ...
    kubectl_cmd = (
        "microk8s",
        "kubectl",
        "run",
        "--rm",
        "-i",
        "--restart=Never",
        f"--namespace={ops_test.model_name}",
        this_pod_name,
        f"--env=AWS_ACCESS_KEY_ID={access_key}",
        f"--env=AWS_SECRET_ACCESS_KEY={secret_key}",
        "--image=amazon/aws-cli",
        "--command",
        "--",
        "sh",
        "-c",
        aws_cmd,
    )

    (
        ret_code,
        stdout,
        stderr,
    ) = await ops_test.run(*kubectl_cmd)
    return ret_code, stdout, stderr, " ".join(kubectl_cmd)

We should make our integration tests k8s agnostic.