* Move method to SkinMinerva
* Turn preparePageContent into a getter that returns the subject
page
* Use getSubjectPage in template
For mobile special pages this now means the page has two .content elements
On those pages I've disabled the initial content element. It also means
various .content <heading> and .content ul rules now apply that need to be
disabled.
While testing several other issues were taken care of - for example
the h2 in errors
Depends-On: I7761396d6a33830f279742be01240796573556a7
Bug: T291871
Change-Id: I13bc4b5dae7aed86eca31ef306212365e1759481
