MDL-47238 core_user: added an error message if guests access user profiles and they aren't allowed to

This fix is a horrible hack, but one I have used for years in tool_editrolesbycap
https://github.com/moodleou/moodle-tool_editrolesbycap/blob/master/yui/capabilityformfield/capabilityformfield.js
and it seems to be reliable.

As an added bonus, I removed the use of YUI2 here.

Also, I fixed the related button in quiz to be GET not POST.

Gradebook items with overridden grades was causing error as Web
Services response

This adds a new setting to display more name information for users
with the viewfullnames capability.

Credit goes to Damyon, thanks.