Upgrade React Router (#3677)

* chore(yarn): Remove react-router

* chore(yarn): Remove react-router-scroll

* chore(yarn): Remove history

* chore(yarn): Add react-router-dom

* chore: Remove usages of react-router-scroll

* refactor: Upgrade to react-router-web

* refactor: Use fork of react-router-scroll

This reverts commit 2ddea9a6c8d39fc64b7d0b587f3fbda7a45a7fa2.

* fix: Issues mentions in the PR feedback

app/javascript/mastodon/features/follow_requests/index.js

@@ -54,6 +54,7 @@ class FollowRequests extends ImmutablePureComponent {
     return (
       <Column icon='users' heading={intl.formatMessage(messages.heading)}>
         <ColumnBackButtonSlim />
+
         <ScrollContainer scrollKey='follow_requests'>
           <div className='scrollable' onScroll={this.handleScroll}>
             {accountIds.map(id =>