Refactor and fix puddle/poddle data retrieval

A new module allows to retrieve the snapshot information in a
(hopefully) more reliable way. Puddle/poodles data are always
printed if available.
Data need to be retrieved from a node with the yum repositories
properly configured, so the controller is used.

Change-Id: I0de1ba6d6224e916e54d5aa2769afbb067e24bb8