chore(monorepo/client): set up some common dependencies

packages/commons/src/i18n.ts

@@ -0,0 +1,10 @@
+export interface Locale {
+    id: string;
+    name: string;
+    /** `true` if the language is a right-to-left one, or `false` if it's left-to-right. */
+    rtl?: boolean;
+    /** `true` if the language is not supported by the application as a display language, but it is selectable by the user for the content. */
+    contentOnly?: boolean;
+    /** The value to pass to `--lang` for the Electron instance in order to set it as a locale. Not setting it will hide it from the list of supported locales. */
+    electronLocale?: string;
+}

packages/commons/src/index.ts

@@ -0,0 +1,3 @@
+export * from "./i18n.js";
+export * from "./options_interface.js";
+export * from "./keyboard_actions_interface.js";