Reland: Change to Shill's IPConfig objects.
Before a recent Shill change, Static and Saved IP config properties were stored in toplevel properties with prefixed keys like kStaticIPAddressProperty.
This change makes use of Shill now exposing these properties nested under a StaticIPConfig and SavedIPConfig dictionary.
This also makes the translation between a list of nameservers and a comma-separated string obsolete.
Original Review URL: https://codereview.chromium.org/
762243002
BUG=411289
TBR=pneubeck@chromium.org
Review URL: https://codereview.chromium.org/
778693004
Cr-Commit-Position: refs/heads/master@{#306669}