Reorganize monorepo structure

* Move all config files to './configs'
* Simplify './scripts' folder.

configs/jest-setupFiles.dom.js

@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) Nicolas Gallagher.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// JSDOM doesn't implement ResizeObserver
+class ResizeObserver {
+  disconnect() {}
+  observe() {}
+  unobserve() {}
+}
+window.ResizeObserver = ResizeObserver;
+
+// JSDOM doesn't provide values for 'clientWidth' etc
+Object.defineProperty(window.document.documentElement, 'clientHeight', {
+  get: function () {
+    return this._jsdomClientWidth || window.innerHeight;
+  }
+});
+Object.defineProperty(window.document.documentElement, 'clientWidth', {
+  get: function () {
+    return this._jsdomClientWidth || window.innerWidth;
+  }
+});