Embed app icon and polish Windows build

scripts/build-linux-docker.sh

@@ -8,7 +8,5 @@ container_id="$(docker create pysentry-linux-builder)"
 mkdir -p "$(dirname "$output")"
 docker cp "${container_id}:/out/pysentry" "$output"
 docker rm "$container_id" >/dev/null
-rm -rf "$(dirname "$output")/assets"
-cp -R assets "$(dirname "$output")/assets"
 
 echo "Built $output"