Convert Flow icons to ooui icons
Depends on ooui patch I1f2e6b9474f06
Most of the changes are minor, as the same icons that were used in
wikiglyph are also available in ooui.
However, some of the more notable changes are:
- Hover behavior: The icons in ooui cannot easily change their colors on hover. As a result, the icons will appear in the hover color (which matches the 'destructive' / 'constructive' / 'progressive' etc variants).
- Using a slightly different 'trash' icon; it's the same one used by VisualEditor and one that already has a 'destructive' variant.
The only remaining wikiglyphs that are left are the 'star', 'unstar'
and 'star-list' icons, which have different visual behavior (hover)
that we will need to work on migrating elsewhere.
For this reason, the wikiglyph module and css files have not been
deleted from the Flow repository yet. We should delete the css files
and remove the module when the star is adjusted and all wikiglyphs