Add DI framework as dependency - Part 2

[CassiusPacheco]

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.

This is pull request is related to the second part of a series of blog posts about Clean, Simple and Composable Routing for iOS Apps.