Add Bear Brotherhood flag

[zenuru-merps]

Colors from https://www.sexualdiversity.org/edu/flags/1075.php
Bear paw illustrated by me since the only other illustrations I could find were CC-BY-SA-3.0.

[brecert]

However the PNG was rendered seems to have cut off the padding around the edges.

[zenuru-merps]

The joy of every application handling SVG rendering slightly differently 🫠
I'll see what I can do to correct that.

[brecert]

I've used resvg to render my svgs while preserving the padding, and I've seen squoosh used by another contributor to render svgs while preserving the padding.