Prism app on initialized

[dansiegel]

Description

The App Initialization has been completely refactored. We no longer strictly follow the MAUI paradigm. PrismApplication is now optional with better Legacy support with a refactored approach that invokes the normal OnInitialized that every Prism.Forms application uses.

// Required ONLY if you do not use the OnAppStart extension on the PrismAppBuilder
public partial class App : PrismApplication
{
    protected override async void OnInitialized()
    {
        await NavigationService.NavigateAysnc("SomeUri");
    }
}

With this PR you can now choose to use EITHER a PrismApplication or simply inherit from the MAUI Application. The Builder has been updated to support a better workflow...

return MauiApp.CreateBuilder()
    .UsePrismApp<App>()
    .RegisterTypes(containerRegistry => {

    })
    .OnInitialized(() => {
        // startup initializations that do not require the container...
    });
    .OnInitialized(container => {
        // startup initializations that require the container to resolve registered services
        // Note that this will be fired prior to the modules loading
    })
    .OnAppStart(async navigationService => await navigationService.NavigateAsync("SomeUri"))
    .ConfigureFonts(fonts => fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular"))
    .Build();

NOTES

When using OnInitialized extensions in the PrismAppBuilder, these are triggered prior to the Modules being loaded as they are loaded internally through this process and it is only after the initializations that the ModuleManager is run.

When using the OnAppStart extension of the PrismAppBuilder, this returns the MauiAppBuilder eliminating the need to reference it as a property to get back to continuing to build the MauiApp.