* React to Razor.Design package removal
* Remove references to packages (Razor.Design, Razor.Extensions) solely used to bring in compiler \ targets
* Target netcoreapp3.0 in samples and tests to allow Sdk to infer values
* Clean up unnecessary workarounds on the build project.
* Remove the need to specify the content root relative to the solution
and use a solution based on an assembly level attribute on the test
assembly created at build time.
* Remove non parameterless constructors.
* Add support for creating specialized factories from the base factory
and keep track of "child" factories for disposal.
* Add support for creating clients that handle cookies and redirects
automatically.