Enhancement

Currently it takes a significant amount of boilerplate to inject a function that can be used to change the locale into the widget tree.

It would be helpful if Dojo could provide a customised widget that injects a function that can be to switch locale into an application widget tree.

The widget should be virtual and have no visual output, but provide an API to for the user to render widgets and nodes with access to the update locale function. This would remove the need for a user to register a new injector or create a custom container to get access to the update locale function.

Related to #256