Sort settings tabs into a logical structure

Fixes https://github.com/vector-im/riot-web/issues/8864

res/css/views/settings/tabs/user/_PreferencesUserSettingsTab.scss

@@ -0,0 +1,27 @@
+/*
+Copyright 2019 New Vector Ltd
+
+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.
+*/
+
+.mx_PreferencesUserSettingsTab .mx_Field {
+    margin-right: 100px; // Align with the rest of the controls
+}
+
+.mx_PreferencesUserSettingsTab .mx_Field input {
+    display: block;
+
+    // Subtract 10px padding on left and right
+    // This is to keep the input aligned with the rest of the tab's controls.
+    width: calc(100% - 20px);
+}