WIP: New GOA provider icons
For 3.32, we need to update the provider icons to the new icon style.
- delete the old PNG icons
- add new scalable and symbolic SVG icons
- adjust build system stuff (I don't know how that works, so help appreciated :) )
- change g-c-c et al. to use the icons at 32px size (or the symbolic when it's used at 16px)