Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  6cf7bbda0ffdaa99c600c25aafaabd760e9b378d

Story 1280 (2/2): Overhaul of image uploading overlay design

Refactor the uploads tutorial and use it for new users in all kind of
uploads.

Remove some unused PNG images, clean up tutorial CSS and fix it for RTL
languages.

Change-Id: I53d72eb1641e1b253ef5b8bb3832918fc654070a