Set up a new icon library based on Phosphor

At present, we use a mixture of Font Awesome and custom icons on our websites. However Font Awesome is freemium, and while the free set is extensive, I'd like to switch to a truly FOSS icon set.

There are three main contenders:

• Bootstrap icons
• Material Symbols
• Phosphor Icons

Ura Design previously redrew several custom icons of ours in the rounded Material Symbols style at a weight of 400: Ura Design Styleguide / Custom Icons.