fixes #3674 - create alias classes System and SystemGroup
fixes #3674 - alias attributes on models
fixes #3674 - change routes to :path => :systems
fixes #3674 - legacy routes to support /hosts
fixes #3674 - modify scoped_search to search on new attributes
fixes #3674 - change UI labels - hosts to systems and hostgroups to system_groups
fixes #3674 - modify v1/v2 api rabl views to include system and system_group