Deprecated remaining naming conventions in preparation for denominator 2.0

This change deprecates remaining naming conventions that use syntax like `getUrl()` or `listByName()` to `url()` or `iterateByName0` to support migration to denominator 2.0.

This also deprecates the list form of ResourceRecordSet, as it gets in the way of extensibility. Previously, RRSet acted as a list of rdata.  Now, users are required to access the rdata as `rrset.rdata()`.  Removing List contract allows ResourceRecordSet to implement a map as necessary (for example, to decorate in new attributes like qualifier).