Add "Webtoon" reading mode

src/assets/icons/svg/WebtoonPageIcon.tsx

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import SvgIcon from '@mui/material/SvgIcon';
+
+export const WebtoonPageIcon = () => (
+    <SvgIcon>
+        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24">
+            <path
+                fill="none"
+                stroke="currentColor"
+                strokeLinecap="round"
+                strokeLinejoin="round"
+                strokeWidth="2"
+                d="M20 2v8a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V2m0 20v-8a2 2 0 0 1 2-2h12a2 2 0 0 1 2 2v8"
+            />
+        </svg>
+    </SvgIcon>
+);