Merge settings and form_editor webpack configs into admin config

Form editor and settings used to have a separate configs because we
they use lodash and it conflicted with underscore in newsletter edtior.
We had recently fixed that conflict and now we can add them to admin.
This also resolves an issue with multiple loading of @emotion/react
[MAILPOET-3654]

webpack.config.js

@@ -193,12 +193,17 @@ const adminConfig = {
       'react-string-replace',
       'prop-types',
       'classnames',
+      'lodash',
+      '@emotion/react',
+      '@emotion/styled',
       'help-tooltip.jsx',
       'listing/listing.jsx',
       'common/index.ts',
     ],
     admin: 'webpack_admin_index.jsx',
     newsletter_editor: 'newsletter_editor/webpack_index.jsx',
+    form_editor: 'form_editor/form_editor.jsx',
+    settings: 'settings/index.tsx'
   },
   plugins: [
     ...baseConfig.plugins,
@@ -237,7 +242,7 @@ const adminConfig = {
 
             // add admin/form_editor_legacy/newsletter_editor shared modules
             const filteredChunks = chunks.filter((chunk) => {
-              return ['admin', 'newsletter_editor'].includes(chunk.name);
+              return ['admin', 'newsletter_editor', 'form_editor', 'settings'].includes(chunk.name);
             });
             return filteredChunks.length > 1;
           },
@@ -354,18 +359,6 @@ const testConfig = {
   },
 };
 
-// FormEditor config
-const formEditorConfig = {
-  name: 'form_editor',
-  entry: {
-    form_editor: 'form_editor/form_editor.jsx',
-  },
-  externals: {
-    'jquery': 'jQuery',
-    'mailpoet': 'MailPoet',
-  },
-};
-
 // Form preview config
 const formPreviewConfig = {
   name: 'form_preview',
@@ -385,18 +378,7 @@ const postEditorBlock = {
   },
 };
 
-// Settings config
-const settingsConfig = {
-  name: 'settings',
-  entry: {
-    settings: 'settings/index.tsx',
-  },
-  externals: {
-    'mailpoet': 'MailPoet',
-  },
-};
-
-module.exports = [adminConfig, publicConfig, migratorConfig, formEditorConfig, formPreviewConfig, testConfig, postEditorBlock, settingsConfig].map((config) => {
+module.exports = [adminConfig, publicConfig, migratorConfig, formPreviewConfig, testConfig, postEditorBlock].map((config) => {
   if (config.name !== 'test') {
     config.plugins = config.plugins || [];
     config.plugins.push(