Seperates out the padlock icon, and adds a tooltip

Fixes https://github.com/vector-im/riot-web/issues/11840

src/components/views/rooms/InviteOnlyIcon.js

@@ -0,0 +1,51 @@
+/*
+Copyright 2020 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 * as sdk from '../../../index';
+
+export default class InviteOnlyIcon extends React.Component {
+    constructor() {
+        super();
+
+        this.state = {
+            hover: false,
+        };
+    }
+
+    onHoverStart = () => {
+        this.setState({hover: true});
+    };
+
+    onHoverEnd = () => {
+        this.setState({hover: false});
+    };
+
+    render() {
+        const Tooltip = sdk.getComponent("elements.Tooltip");
+        let tooltip;
+        if (this.state.hover) {
+            tooltip = <Tooltip className="mx_InviteOnlyIcon_tooltip" label={_t("Invite only")} dir="auto" />;
+        }
+        return (<div className="mx_InviteOnlyIcon"
+          onMouseEnter={this.onHoverStart}
+          onMouseLeave={this.onHoverEnd}
+        >
+          { tooltip }
+        </div>);
+    }
+}