Router options to work with the ms-seo package

Adds SEO information to routes for [ms-seo](https://github.com/DerMambo/ms-seo) package. Description works with `Blog.config()` on the client side for the `blogIndex` template. For blog posts, description is either based on an optional `metaDesc` set during blog creation or the excerpt. I have not yet created the corresponding template fields for `metaDesc`.