fixes #3928 - API v2 - update os_default_templates for operating system

Fixes #3720 - Add description field to operatingsystem

fixes #3491 - API v2 rabl templates base, main, show for each controller

fixes #3768 - API v2 child nodes should not have an object root for each object

fixes #2931 - API v2 hosts JSON response, add *_name for each *_id

fixes #3018 - API v2 metadata for pagination, search, order in index collection json response

fixes #3011 - default root node name for api collections json response to :results but make it configurable

fixes #3510 - plugin interface for registering a plugin, updated menu system

fixes #2763 - correcting doco links

fixes #3017 - split APIv2 controllers from v1 parents