Hygiene: Standardise on our icon usage

Standardise our icons across the project
including following components:
* clean up templates
* user profile talk icon
* nearby refresh icon
* special uploads upload button
* pagelist images
* user icons
* page actions icon
* left menu icons
* main navigation icons

Kill
* low res icons on main menu
* Language code for cached pages (added in February)
* Use of 30px icons in favour of 32px

Take care to ensure changes work for cached pages

Change-Id: I36b77cfa605d561fcbb8a5ed84fcbfd87722411f
Merge "Hygiene: Standardise on our icon usage"