Move security-related dialogs to a common directory

res/css/views/dialogs/security/_KeyBackupFailedDialog.scss

@@ -0,0 +1,41 @@
+/*
+Copyright 2018 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_KeyBackupFailedDialog .mx_Dialog_title {
+    margin-bottom: 32px;
+}
+
+.mx_KeyBackupFailedDialog_title {
+    position: relative;
+    padding-left: 45px;
+    padding-bottom: 10px;
+
+    &::before {
+        mask: url("$(res)/img/e2e/lock-warning-filled.svg");
+        mask-repeat: no-repeat;
+        background-color: $primary-fg-color;
+        content: "";
+        position: absolute;
+        top: -6px;
+        right: 0;
+        bottom: 0;
+        left: 0;
+    }
+}
+
+.mx_KeyBackupFailedDialog .mx_Dialog_buttons {
+    margin-top: 36px;
+}