prelude: update theme to incorporate the new 'material icons fonts'
prelude: update theme to incorporate the new 'material icons fonts'

* insert woff2 fonts
* include ttf font as 'material_icons_font_ttf'

Signed-off-by: Ralf Zerres <a55c5beace021459791f5070a9a90148cd697b8f@networkx.de>

redox-os/orbtk