Add short-eared owl as the Owltide mascot and icon

I've settled on a short-eared owl (Asio Flammeus) to serve as the mascot
and icon for Owltide. This is not a settled and final decision, but
rather a branding that's good enough for now.

To create the mascot I sketched some owls that I have saved to
/assets/mascot/owl-sketch.png and then selected one I liked.  Going
clockwise from the top right the sketches were based on the reference
photos [1], [2], and [3] found by searching for "owl" on Wikimedia
Commons.  I then lightly refined it to work as a small icon.

To avoid confusing terms that only make sense for software the artworks
are licensed under the Creative Commons Attribution-ShareAlike 4.0
License.  This has a similar spirit to the AGPL and ensures that should
improvements be made upon them they can be incorporated in the project.

[1]: https://commons.wikimedia.org/wiki/File:Athene_cunicularia_-near_Goiania,_Goias,_Brazil-8_edit.jpg
[2]: https://commons.wikimedia.org/wiki/File:Hibou_des_marais.jpg
[3]: https://commons.wikimedia.org/wiki/File:Uhu-muc.jpg

nuxt.config.ts

@@ -14,6 +14,9 @@ export default defineNuxtConfig({
 			htmlAttrs: {
 				lang: "en",
 			},
+			link: [
+				{ rel: "icon", type: "image/x-icon", href: "/favicon.ico" },
+			],
 		},
 	},
 	runtimeConfig: {