Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

webapp/channels/babel.config.js

@@ -0,0 +1,57 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+const config = {
+    presets: [
+        ['@babel/preset-env', {
+            targets: {
+                chrome: 66,
+                firefox: 60,
+                edge: 42,
+                safari: 12,
+            },
+            modules: false,
+            corejs: 3,
+            debug: false,
+            useBuiltIns: 'usage',
+            shippedProposals: true,
+        }],
+        ['@babel/preset-react', {
+            useBuiltIns: true,
+        }],
+        ['@babel/typescript', {
+            allExtensions: true,
+            isTSX: true,
+        }],
+    ],
+    plugins: [
+        'lodash',
+        '@babel/plugin-proposal-class-properties',
+        '@babel/plugin-proposal-object-rest-spread',
+        'react-hot-loader/babel',
+        'babel-plugin-typescript-to-proptypes',
+        [
+            'babel-plugin-styled-components',
+            {
+                ssr: false,
+                fileName: false,
+            },
+        ],
+    ],
+    sourceType: 'unambiguous',
+};
+
+// Jest needs module transformation
+config.env = {
+    test: {
+        presets: config.presets,
+        plugins: config.plugins,
+    },
+    production: {
+        presets: config.presets,
+        plugins: config.plugins.filter((plugin) => plugin !== 'babel-plugin-typescript-to-proptypes'),
+    },
+};
+config.env.test.presets[0][1].modules = 'auto';
+
+module.exports = config;