Unify all desktop icons on Mac, Win and Linux to fit with the correct, updated brand guidelines here: https://www.blender.org/about/logo/

This is using :

PANTONE 716 C = #EA7600 (RGB 234 118 0)
PANTONE 647 C = #236192 (RGB 35 97 146)

Thanks to Yevgeny Makarov (jenkm) for compiling this icon update.

See T63623