Add the ability to perform non-Shell page navigation

[Dreamescaper]

Currently we have ShellNavigationManager for url-based navigation, but it has its own limitations:

• Can be used with Shell only
• Cannot pass arbitrary parameters, only the ones based on URL
• Cannot be used with modals (we have ModalContainer for modals, but it's not very convenient)

I would suggest to add a service for navigation, which would allow to work with components:

interface INavigationService
{
    Task PushAsync<T>(Dictionary<string, object> arguments = null, bool animated = true) where T: IComponent;
    Task PushModalAsync<T>(Dictionary<string, object> arguments = null, bool animated = true) where T: IComponent;

    // Optional, just for convenience (as you can do same now via NativeElement property)
    Task PopToRootAsync(bool animated = true);
    Task PopModalAsync(bool animated = true);
    Task PopAsync(bool animated = true);    
}

This way navigation would look smth like that:

       @inject INavigationService NavigationService

	async Task Navigate()
	{
		await NavigationService.PushAsync<MyPage>(new()
		{
			[nameof(MyPage.Parameter1)] = arg1,
			[nameof(MyPage.Parameter2)] = arg2
		});
	}

It would be great to design this service with extensibility in mind, so that I could, for example, add extension method ShowPopupAsync to display XCT's Popup.

Open questions:

• How to name it to avoid confusion? We have ShellNavigationManager, we have NavigationManager from web Blazor, would NavigationService be fine?
• Would it make any sense to merge it with existing ShellNavigationManager ?
• Can I always use Application.Current.MainPage.Navigation to get INavigation?
• Is there any Navigated event we could use to dispose the renderer when the page is closed?

[Dreamescaper]

Requires #418 .

[Dreamescaper]

We could also provide RenderFragment overloads to allow a bit exotic syntax:

async Task Navigate()
{
    await NavigationService.PushAsync(
        @<MyPage Parameter1="arg1" Parameter2="arg2" />
    );
}