Add support for canonical links on blog posts and other app pages

Currently you can set canonical links on regular pages, but you can't easily do it on blog posts or other blog pages. This would also apply to other apps. Blog posts would have a canonical link to themselves automatically, but there could be the ability to specify a different URL. Other pages should also probably have a canonical link to themselves. It's not a good idea to have paginated pages be canonicalized to the app home page as that can prevent search engines from indexing them. This could be turned on or off with a setting within the app. Resources -,page%20will%20display%20different%20elements. - -