NEW Adding CMS sitetree filter to see the current 'live' site

This adds a new filter that will show a content editor what the current published site-tree
looks like for a visitor. This helps when there is a lot of drafted content that get included
in the default filter 'All Pages'
Merge pull request #1063 from stojg/pull/published-pages-cmsfilter

NEW Adding CMS sitetree filter to see the current 'live' site