Fixes #5723 - Show hostgroups inherited via config groups in puppetclass

@tbrisker, I don't think the UI needs to show all the hostgroup descendants. For example, if puppetclass is associated with "Base" hostgroup and this has 100 descendants, it's not so crucial to show this on the UI index page. 

What do people think about adding a column for "Config Groups" on the Puppetclasses index page to show the "direct" config groups? In this case, the hostgroups column would also revert back to showing just the "direct" hostgroups and not all (inherited through parent and/or config group).