mod_rest: Support parameters in callback URL E.g. rest_callback_url = "http://myapi.example:5000/api/{kind}/{type}" which results in e.g. requests to /api/message/chat Allows using path routing in web frameworks for dispatch instead of having to pick apart the payload to further dispatch it.

--% conflicts: mod_bookmarks
module:log("info", "mod_bookmarks has been deprecated, now loading mod_bookmarks2")
module:depends("bookmarks2")