Make edit button permissions work on alpha lazy loaded pages

Replace standard getGroups function on mw.user to avoid an
async call.

Deal with inconsistencies using M.getCurrentPage reveals - page title can
have _ characters and this effects editor header

Bug: 60104
Change-Id: If665c364cd9d0c93f3d744a9ef183aea49b0f3b0
Merge "Make edit button permissions work on alpha lazy loaded pages"