PLT-6215 Major post list refactor (#6501)

* Major post list refactor

* Fix post and thread deletion

* Fix preferences not selecting correctly

* Fix military time displaying

* Fix UP key for editing posts

* Fix ESLint error

* Various fixes and updates per feedback

* Fix for permalink view

* Revert to old scrolling method and various fixes

* Add floating timestamp, new message indicator, scroll arrows

* Update post loading for focus mode and add visibility limit

* Fix pinning posts and a react warning

* Add loading UI updates from Asaad

* Fix refreshing loop

* Temporarily bump post visibility limit

* Update infinite scrolling

* Remove infinite scrolling

webapp/utils/utils.jsx

@@ -12,6 +12,7 @@ import Constants from 'utils/constants.jsx';
 var ActionTypes = Constants.ActionTypes;
 import Client from 'client/web_client.jsx';
 import * as UserAgent from 'utils/user_agent.jsx';
+import {Posts} from 'mattermost-redux/constants';
 
 import {browserHistory} from 'react-router/es6';
 import {FormattedMessage} from 'react-intl';
@@ -1194,7 +1195,7 @@ export function clearFileInput(elm) {
 }
 
 export function isPostEphemeral(post) {
-    return post.type === Constants.PostTypes.EPHEMERAL || post.state === Constants.POST_DELETED;
+    return post.type === Constants.PostTypes.EPHEMERAL || post.state === Posts.POST_DELETED;
 }
 
 export function getRootId(post) {