logo: Update favicon to 2016 logo

This updates the favicons to use the new logo and also uses the Cockpit
blue that we are used to.

Process for getting the inverted logo with a blue circle with a white
plane I've taken the inner circle of the Cockpit logo and made the plane
white on top of it. This way the outer circle which would've been there
is not creating unnecessary whitespace.

Signed-off-by: Freya Gustavsson <freya@venefilyn.se>

Author: Venefilyn