Pulled description, title, and keywords out of templates and into i18n

# What's Changed

* Pulled description, title, and keywords into en.yml, this should make them easier to update, it's dryer.
* Made them yield to view defined descriptions, keywords, and titles. 

# What's next
* Have a look at the image uploader stuff @rickcarlino is putting together.
* Start implementing @roryaronson's garden page (entering final stage of starting to have guides actually respond to user settings!)