Pagination on Rackspace DNS records

This issue has popped up numerous times for Rackspace DNS _zones_, but was never corrected for _records_.

This issue #1172 is identical, but was closed referencing #1535, which is pagination for _zones_.

The max records per zone (by default) with Rackspace is 500, and the page limit is 100 by default.  Since the max records is relatively low, I've added a quick fix with the #all! method for our pipeline as this is a very crucial feature.

I hope to refine this into an #each method with test coverage, but I needed a quick fix for now, and wanted to make the issue known.