Use the DependencyContainer framework to inject containers in the 
routers which will be responsible for instantiating the whole flow of 
the app.

The Graph's container should register and resolve all dependencies of 
the app. In order to do it the container must be passed down to every 
Router.

No other classes besides Routers should have access to it. Routers are 
the only responsible for instantiating new screens and they are 
in charge of injecting all necessary dependencies into them.

A DependencyContainer extension has been added to the testing target
in order to ensure that all interfaces registered in the container
have been swapped for Mock classes instead.

Also, a RouterMock implementing Router spy methods and all Routes is 
used to test all routes are executing the correct flow using the correct
transition.

Finally, a RoutesMock which implements all Routes interfaces has been
added to ensure all routes being triggered from the view models are
properly tested.