[FEATURE] Add retry to spec tester

[dblock]

Is your feature request related to a problem?

Some APIs in OpenSearch create tasks that need to be awaited for. Add support for a predictable retry.

What solution would you like?

In the following example retry twice after 60 seconds if the status code doesn't match the expected one.

retry: 2
retry_after: 60

Sometimes status code isn't enough and we are waiting for a field value. Today we check for response schema. In addition I think we can add a response_body that expects some values, then retry: 2 makes sense.

retry: 2
response_body:
    status: "CREATED"

Do you have any additional context?

Coming from #315 (comment)