WIP: Add .NET MAUI Blazor Hybrid + Web App solution template

[Eilon]

Description of Change

NOTE: This is a Work In Progress!

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:

And here's what the rough layout of files looks like (some details still being figured out):

And when you run the apps they look the same (because all the UI components are shared):

The various options relevant to .NET MAUI and to Blazor Web are available in this project, with the exception of no Authentication options (at this time).

Issues Fixed

Fixes #1069