[GHA] Prepare to run VSCode extension snapshot builds

.github/scripts/gen-vscode-link-bullet.sh

@@ -0,0 +1,8 @@
+id=$1
+label=$2
+download_url_root=$3
+
+vsix_file=`aws s3 cp s3://$AWS_S3_BUCKET/snapshot/vscode-extensions/$id/ . --exclude "*" --include "*.vsix" --exclude "*/*" --dryrun | head -n 1`
+if [ ! -z "${vsix_file}" ]; then
+  echo "<li>${label}: <a href=\"${download_url_root}/snapshot/vscode-extensions/${id}/${vsix_file}\">${vsix_file}</a></li>"
+fi