* Replace JS use in feather icons with SVG
There's still JS for the toggle functionality, but no more Javascript to
refresh the icons.
* Add support for SimpleIcons
This is based on https://github.com/simple-icons/simple-icons-font,
release 13.3.0, with font and css copied in.
Since Feather Icons and Simple Icons differ in purpose and naming
scheme, old social icons still point to feather. To add simple icons,
just prefix their name with "simple", e.g.
- name: "mastodon"
icon: "simple:mastodon"
url: "https://foo.social/@foo"
Resolvesathul/archie#69, athul/archie#95, athul/archie#49
Patrick Georgi
Hyacinthe Cartiaux
Harrison Sand
athul