Create presenter for content_item

This will need to be split at some point in the not to distant future
into a case study presenter and a generic edition like presenter. But
for the moment it is in a generic content item presenter.

Also use components to make the page closer represent the direction it
is heading in.
Add basic styling for case study page
Add format names for heading context

Add in the en localizations of the different formats and use
format_display_type to create a context for the heading.