Move the shared ESLint plugin/config into the monorepo (#24670)

* Move the shared ESLint plugin/config into the monorepo

* Add peer dependencies to ESLint plugin

webapp/channels/src/components/external_link/index.tsx

@@ -1,7 +1,7 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-/* eslint-disable mattermost/use-external-link */
+/* eslint-disable @mattermost/use-external-link */
 
 import React from 'react';
 import {useSelector} from 'react-redux';

webapp/channels/src/components/size_aware_image.jsx

@@ -1,7 +1,7 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-/* eslint-disable mattermost/use-external-link */
+/* eslint-disable @mattermost/use-external-link */
 
 import classNames from 'classnames';
 import PropTypes from 'prop-types';