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

.gitignore

@@ -6,6 +6,7 @@ node_modules
 /webapp/dist
 jobserver
 npm-debug.log
+webapp/yarn-error.log
 mattermost.mattermost-license
 config/mattermost.mattermost-license