[Enhancement] Support IInitialize with Dialog ViewModel

Summary

In addition of the IDialogAware, provide a Dialog ViewModel initialization, similar of IInitialize and IInitializeAsync of page navigation.

API Changes

Add the equivalent of IInitialize & IInitializeAsync interfaces for the Dialogs.

public interface IDialogInitialize
{
    void Initialize(IDialogParameters parameters);
}

public interface IDialogInitializeAsync
{
    Task InitializeAsync(IDialogParameters parameters);
}

Intended Use Case

Support the synchronous and asynchronous initialization of a Dialog ViewModel.

Start by locating the existing IDialogAware implementation and the IInitialize and IInitializeAsync interfaces used by page navigation. Add equivalent synchronous and asynchronous dialog initialization support using IDialogParameters, then verify that dialog ViewModels can receive those initialization calls.