This change adds three new properties for VirtualKeyboardSettings.

- locale: Defines the default locale, can also be used to change
  the current language.
- availableLocales: A list of built-in locales.
- activeLocales: Application defined list of active locales.

Task-number: QTRD-3332
Change-Id: Ia9e69f54501ec7ad7680a6167546b52d0972e2dc
Reviewed-by: Mitch Curtis <mitch.curtis@theqtcompany.com>