Add virtual workbook / config-in-skeleton classes

This patch introduces a new abstraction 'skeleton-workbook'
for representing a system configuration.  At present it is
pulled in by the skeleton recipe so the requirement on what is
implemented by a package providing obmc-phosphor-workbook is something
compatible with the existing System.py python modules in skeleton.

Additionally this patch adds a new recipe for each system using
a configuration file from skeleton today, and a class for common
configuration.

This enables a couple of things:
 - No need to patch skeleton.service for each system.
 - New systems don't have to put their configuration in the skeleton
     repository.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
11 files changed