first step towards nested blog index
add tree-view to posts
refactory `url_with_updated_param` helper
rename blog tab to 'posts'
Revert "first step towards nested blog index"

This reverts commit 1a3fe9b3213de59d3f650c82e48a34341c47b2a8.
Merge branch 'add-pages-tree-style-to-refinery-blog'