List of all icons in the package
It would be nice to have a way to get a list of all icons.

I am creating an icon picker. And I can't create support for phosphor_icon (without a lot of extra code).

It would be nice to have something like this.

`PhosphorIcons.allIcons()`

Exporting this in a way would be nice:

https://github.com/phosphor-icons/flutter/blob/main/example/lib/constants/all_icons.dart