Navigate without context

[udaymrx]

Add ability to navigate without the need of context,
It will be really helpful at places like controller, where we don't have context and need to do some kind of navigation (to seperate the business logic from the UI completely), but we can't.

[csells]

You don't need context to call GoRouter.go() or GoRouter.push; you can make your GoRouter instance global and call it from wherever you need.