Add get_next and use it from _paginate_response as well

[Disruption]

Changes

This is a QoL update.
This PR adds a public entrypoint "get_next" to fetch the next page of results after an existing response.
This allows client users to paginate manually without having to do all the boilerplate checks and without having to explicitly use the field name for "next" or having to control page size and result size manually (via $top and $skip parameters passed to the request).