Make settings as a clean architecture

src/content/client/SettingClient.ts

@@ -0,0 +1,17 @@
+import Settings from '../../shared/Settings';
+import * as messages from '../../shared/messages';
+
+export default interface SettingClient {
+  load(): Promise<Settings>;
+
+  // eslint-disable-next-line semi
+}
+
+export class SettingClientImpl {
+  async load(): Promise<Settings> {
+    let settings = await browser.runtime.sendMessage({
+      type: messages.SETTINGS_QUERY,
+    });
+    return settings as Settings;
+  }
+}