(bug 27911) Standardise Apple Touch icons for all projects

This commit does the following things:
* (1) It standardises the location of Apple Touch icons for our
projects by putting them into one directory on bits.wm.org;
* (2) It adds Apple Touch icon for all Wikinews projects, using
the icon used by the English Wikinews;
* (3) It removes broken links for foundationwiki, metawiki,
officewiki and wikimania2005wiki — which never had any
Apple Touch icons, yet had links to them inside the HTML <head />
tag — see bug 44680.
* (4) It removes broken link to an icon on test wiki, which has
apparently been deleted since.

I'm using the same format that's already used for general favicons.
This way, users will be able to define Apple Touch icons on a per-
family or even per-wiki bases, should that prove neccessary.

What this commit does not do, is that it does not create new icons
nor change existing ones (with the exception of the Wikipedia icon
per bug 47383); I'm merely moving them to a new directory.

Per Krinkle's comment, since we're using a 30-day cache period, I'm
keeping the current icons for commonswiki, usabilitywiki, and all
Wikipedia and Wiktionary wikis so that we do not point to 404 files
(mediawikiwiki is currently pointing to a non-existing icon anyway).

Bug: 27911
Change-Id: Ib5554c547295d9b53b4f554e2773a4d7c14f8c6a
Merge "(bug 27911) Standardise Apple Touch icons for all projects"