Normalize asset route
Remove uneeded routes.
Extend asset route.

Allow posts to have "private" assets. (e.g. a post has some images.
There is no need to have those images trashing the "global"/"root" asset
dir. Because only that specific post will use that asset.) This also
allows for a post to be self-contained. Each post/directory contains
everything it needs to be a full post.
Merge branch 'feature/asset-route-normalizing'