Moodle Community theme cleanup

During the development of the new shiny Moodle Community, the contents for some pages was initially implemented via Mustache templates. It was then reimplemented to use HTML blocks (allowing for the content translation filter features, inline editing etc).

However, some relics of the original implementation seem to be still present in the theme codebase:

• Anything related to the moodleorg_pagecontent (method, 2x template lines)
• Everything in templates/local/*

Relics like this are confusing for future contributors to the theme. Better to get rid of them while we remember for what they were for.

Something for aya.saad, thanks in advance!