PLT-4431 Add post queuing to the webapp (#4800)

* Add post queuing to the webapp

* Add more abstraction

webapp/components/create_comment.jsx

@@ -196,10 +196,7 @@ export default class CreateComment extends React.Component {
 
         GlobalActions.emitUserCommentedEvent(post);
 
-        PostActions.createPost(post, false,
-            () => {
-                // DO nothing.
-            },
+        PostActions.queuePost(post, false, null,
             (err) => {
                 if (err.id === 'api.post.create_post.root_id.app_error') {
                     this.showPostDeletedModal();