Break themes out into a separate file

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/themes.js

@@ -0,0 +1,24 @@
+/*
+Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
+
+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 {_td} from "./languageHandler";
+
+export const DEFAULT_THEME = "light";
+
+export const THEMES = {
+    "light": _td("Light theme"),
+    "dark": _td("Dark theme"),
+};