Replace Fira with FiraGO

[skade]

Design Feature Request

Summary

FiraGo is an extended version Fira with better support for non-latin fonts.

Motivation

This might help in i18n efforts.

Drawbacks

Potentially increased font file size.

[skade]

Confirmed: Fira doesn't render characters necessary for the Turkish translation.

[skade]

Wrong, Fira renders correctly, our headlines are in Alfa Sans, see #858

[XAMPPRocky]

Closing as a duplicate of #867