Add icon for Nostr

[snarfed]

I've started using Nostr a bit, it'd be nice to have a dedicated icon for Nostr links! It has a bunch of different clients on different domains, here's an incomplete list:

• astral.ninja
• nos.social
• iris.to
• snort.social
• app.coracle.social
• primal.net
• habla.news
• nostr.band

Here are a couple possible icons:

[dshanske]

https://github.com/mbarulli/nostr-logo - Seems someone came up with an SVG version.

[dshanske]

Resolved via be1c4c6