working UGC content upload with multi-upload support

nonpacks/static/js/version_upload.js

@@ -0,0 +1,8 @@
+// "New version" page: uses the shared uploads.js engine for the version file
+// (single slot). On submit the pending version temp is moved into the project.
+(function () {
+    const pending = JSON.parse(
+        (document.getElementById('packs-pending-uploads') || { textContent: '[]' }).textContent
+    );
+    PacksUploads.init({ pending: pending });
+})();