PLT-2672 Refactored posts view with caching (#3054)

* Refactored posts view to use view controller design

* Add post view caching

* Required updates after rebase

* Fixed bug where current channel not set yet was causing breakage

webapp/components/channel_view.jsx

@@ -7,7 +7,7 @@ import React from 'react';
 import ChannelHeader from 'components/channel_header.jsx';
 import FileUploadOverlay from 'components/file_upload_overlay.jsx';
 import CreatePost from 'components/create_post.jsx';
-import PostsViewContainer from 'components/posts_view_container.jsx';
+import PostViewCache from 'components/post_view/post_view_cache.jsx';
 
 import ChannelStore from 'stores/channel_store.jsx';
 
@@ -70,7 +70,7 @@ export default class ChannelView extends React.Component {
                 <ChannelHeader
                     channelId={this.state.channelId}
                 />
-                <PostsViewContainer/>
+                <PostViewCache/>
                 <div
                     className='post-create__container'
                     id='post-create'