Device Manager - add new labsed session manager screen (PSG-636) (#9119)

* add feature_new_device_manager labs flag

* add generic settings tab container

* settingstab section styles

* add session manager tab to user settings

* add sessions tab case to UserSettingDialog test

* fussy import ordering

* remove posthog tracking

* i18n

src/components/views/settings/tabs/user/SessionManagerTab.tsx

@@ -0,0 +1,26 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+
+import { _t } from "../../../../../languageHandler";
+import SettingsTab from '../SettingsTab';
+
+const SessionManagerTab: React.FC = () => {
+    return <SettingsTab heading={_t('Sessions')} />;
+};
+
+export default SessionManagerTab;