FR: Include Liberation Mono font

[iahung2]

LiberationMono-Regular.ttf looks pretty good with ecode. All problems with anti-aliasing and sub-pixel hinting are gone.

https://github.com/liberationfonts/liberation-fonts/files/7261482/liberation-fonts-ttf-2.1.5.tar.gz

[SpartanJ]

I was going to say no, but I might given that in comes with more glyphs. I'm going to play around a little bit and decide it. The problem in providing more fonts is that they are not directly selectable to the user on some distributions (basically on AppImage), so I need to fix that first.