Makes sense, however when it comes to enabling the language-associated keyboard when changing locale (FTE or language from Settings) aren't we interested to enable only built-in keyboard and let the user enable 3rd-party ones from the Keyboard Settings manually? Or should we enable all keyboard layouts specified under a certain language in `keyboard_layouts.json`?

Thus we can consider a more explicit structure:
```js
"ar": {
        "built-in": {"layoutId": "ar", "appOrigin": "keyboard.gaiamobile.org"},
       "3rd-party": [
            {"layoutId": "ar-1", "appOrigin": "some-3rdparty.ime.com"},
            {"layoutId": "ar-2", "appOrigin": "other-3rdparty.ime.com"},
        ]
},
```