Update fontawesome to a newer version

[han-f]

We use fontawesome icons for the capacity building sections. The icons that load look a bit outdated compared to the icons on the fontawesome website. Would it be possible without breaking things to update to a newer version of fontawesome to improve the overall look and feel?

[wingechr]

@han-f let's have a look at this together. there is probably a way to make it look better using styling options.