Use 'pagetitle' in content language

It often happens that wiki sysops want to change it site wide, especially
when they want to change the format (eg, have {{SITENAME}} removed, or
replace the hyphen with a middot).

Bug: 48701
Change-Id: Iaf00fca1e89ae022c348c4fa0de32b998d7921a1
Merge "Use 'pagetitle' in content language"