There were some minor annoyances with the WPF projects.
1. WpfTerminalTestNetCore was in an unnecessary same-named subdirectory
2. The build started throwing deprecation warnings because `netcoreapp3.0` is not LTS and is going away.
This commit introduces a new project that lets you F5 a working instance
of the Wpf Terminal Control.
To make the experience as seamless as possible, I've introduced another
solution platform called "DotNet_x64Test". It is set to build the WPF
projects for "Any CPU" and every project that PublicTerminalCore
requires (including itself) for "x64". This is the only way to ensure
that when you press F5, all of the native and managed dependencies get
updated.
It's all quite cool when it works.
