Update nginx front-end configuration for Penpot

Summary:
When Penpot has been updated to 1.19.3-10698-g1eaf7b2b4, font support
was broken: when an user select a new font, text stays in the default font.

Console showed 404 errors on /internal/gfonts/css URL, missing from our nginx
configuration. Penpot nginx configuration has indeed been updated to proxy
Google Fonts requests locally.

Test Plan: Deploy on docker-002 for https://design.nasqueron.org

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D3295