Update the ASP.NET Core hosted Blazor WebAssembly template to use _Host.cshtml

[danroth27]

Currently the ASP.NET Core hosted Blazor WebAssembly uses a static index.html file. It would be more flexible to instead use a _Host.cshtml file like the Blazor Server template does. The root App component could then be setup using the component tag helper with RenderMode.WebAssembly. This would make it easier for the user to turn on prerendering if that's what they want to do. Note that I'm not proposing that we enable prerendering by default, as that adds a bunch of additional complexity for the user.

[javiercn]

How do you want this to work with PWAs?

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[danroth27]

From discussing with Javier: We would potentially need to generate hashes for a couple of things on the fly, since the content of the "index.html" can now be dynamic.