Made multi-format multi-resolution favicons.

[MicahGale]

Description

I noticed that on DuckDuckGo our favicon doesn't show up in the results page:

Looking into how Bing handles this (most of the backend for DuckDuckGo), this is because we only provide an SVG icon. This forum post recommends providing a PNG, and including it in the sitemap. I couldn't get it to work in the sitemap though, so I'm ignoring that, and SO doesn't say this is necessary.

Another SO thread recommends providing lots of options. I decided we should do most of those. I couldn't get inkscape to export ICO so I think we can just ignore IE support. The new extension does work in adding multiple favicon options:

It is intentionally ordered from best to worst options.

Checklist

• I have performed a self-review of my own code

[tjlaboss]

I added a 32x32 ico. Add that to the docs and then we'll merge

[MicahGale]

I added a 32x32 ico. Add that to the docs and then we'll merge

Added!