ava: Generate Locale menu automatically (#4243)

Currently in `MenuMainBarView.axaml` we list all available languages and hardcode the language name with the language key.
It's a bit bad beause if we want to add a new language, we have to edit the `csproj` and the `axaml` with the translated language name and the language code.
I've put all translations in their respective locale files, add code into `MainMenuBarView` constructor to generate the menu automatically. Now we just have to edit the `csproj` if we want to add a new language.

Ryujinx.Ava/Assets/Locales/zh_TW.json

@@ -1,4 +1,5 @@
 {
+  "Language": "繁體中文",
   "MenuBarFileOpenApplet": "打開小程式",
   "MenuBarFileOpenAppletOpenMiiAppletToolTip": "打開獨立的 Mii 小程式",
   "SettingsTabInputDirectMouseAccess": "直通滑鼠操作",
@@ -610,4 +611,4 @@
   "UserProfilesRecoverLostAccounts": "恢復遺失的帳號",
   "Recover": "恢復",
   "UserProfilesRecoverHeading": "在以下帳號找到了一些遊戲存檔"
-}
+}