Make some navigation classes and methods public for extended usability

[BackPackerDz]

This PR updates the access modifiers of ViewRouteListener and NavigationViewRouter, along with three of its methods (findRouteFrom, updateLocation), to public. These changes are essential to allow developers to handle rerouting more directly within their applications. Without these modifications, developers are forced to rely on less desirable solutions such as duplicating internal code or employing fragile workarounds. Making these classes and methods public simplifies the development process and enhances the flexibility of the navigation functionality.

I welcome feedback on these changes and am open to discussing alternative approaches. Please share any suggestions or insights you have.

Several useful classes in the library are internal, limiting their direct usability. I’d appreciate insights into the decision for such accessibility settings to align our development efforts better.