Let template access MSBuild properties.

[voroninp]

I set RootNamespace in Directory.Build.prop file and it differs from the assembly name.
However, when I create Blazor Web App from the template and name project MyWebApp, Porgram.cs file contains this line:

using MyWebApp.Components;

However, generated razor classes are placed into <RootNamespace>.Components.
It would be nice, if template could set namespace not from the project name, but msbuild properties as well, if they are defined.