Directly using Crystal's ECR seems to be causing issues, so
don't use kemal's 'render' macro and patch 'content_for' to
have the same behavior as before Kemal v1.1.1
* Extract feed routes from invidious.cr
* Removes the deprecated route for /feed/top
* Deprecate /view_all_playlist & use /feed/playlists
* Move feed views into their own directory
* Add haltf method to halt current route context
* Change status_code + return blocks to use haltf
* Set appropriate response headers for RSS routes
