Prepare initial site content

Summary:
A vertical split design with colors based on the background photo
will allow to browse the available documentations.

Such documentations are listed in data/docs.yml.

The JS code slightly animates the site, and offers an easter egg.

Test Plan: npm run build

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1030