We add a new theme config so the theme can say it supports font-awesome.
If this is true, the pix_icon renderer will call a mapping function to map
from the moodle style t/edit to a font-awesome style fa-cog icon name. Then the renderer
will either render an image tag for old icons - or an accessible font-awesome <i> tag.
This mostly works - but there are some places where we don't use the pix icon renderer, and
we directly create image tags with pix_url image sources. These will need updating (Atto icons,
drag and drop move icons, editpdf icons).
I missed all the entry pages when converting from set_abc() and get_abc() to set('abc', ) and get('abc').
Also fixed a wrong namespace for core_competency\external\performance_helper
Damyon Wiese