Add .NET MAUI Blazor Hybrid + Web App solution template

[Eilon]

Description of Change

This adds a new template to dotnet new and in Visual Studio that creates a solution with .NET MAUI Blazor Hybrid app with a Blazor Web app, which share common code in a Razor Class Library project.

Here's what you'll see from the command line:

And from VS you get this template:

With these options:

And here's what the rough layout of files looks like:

And when you run the apps they look the same (because all the UI components are shared) - and include additional sample code for an IFormFactor interface to show how to write platform-specific services:

Most of the options from the Blazor Web project template are also available in this new template.

Issues Fixed

Fixes #1069

(This is a replacement for PR #21867)