Add rate limit management so that module's API calls avoid failure when exceeding the rate limit

[mkearey]

We rarely hit the limits but have done in the past, mainly when managing a large zone with hundreds of records and a lot of changes. It results in a playbook failure.

Its my understanding that the NS1 Ansible module does not currently perform any rate limit management for API calls.

ns1-python has two options currently:
https://github.com/ns1/ns1-python/blob/master/examples/rate-limiting.py

The API docs about the rate limits:
https://www.ibm.com/docs/en/ns1-connect?topic=api-rate-limiting

We would like to see an option to enable rate limit management for API calls the module makes. It will help avoid playbook failures as a result of exceeding the rates permitted.