Deprecate API v2 (#7761)

* deprecate api-v2

* remove v2 test helpers

* remove unused string

website/server/libs/collectionManipulators.js

@@ -0,0 +1,22 @@
+import {
+  findIndex,
+  isPlainObject,
+} from 'lodash';
+
+export function removeFromArray (array, element) {
+  let elementIndex;
+
+  if (isPlainObject(element)) {
+    elementIndex = findIndex(array, element);
+  } else {
+    elementIndex = array.indexOf(element);
+  }
+
+  if (elementIndex !== -1) {
+    let removedElement = array[elementIndex];
+    array.splice(elementIndex, 1);
+    return removedElement;
+  }
+
+  return false;
+}