Net Core - Support for compiling with .Net Core 3.1

- Make Wpf/WinForms/OffScreen projects target AnyCPU
Only the VC++ projects are platform specific now.
- Remove BrowserSubProcess project reference
Not needed as we now have a standalone exe
- Add OffScreen example
- Add WPF Example project
- Fix some compile errors for main solution
- Add BrowserSubProcess executable
- JavascriptObjectRepository remove isAsync param
Rather than throw exception remove the option
- BrowserSubprocess Exclude the WCF specific code from the netCore project
- Add some ifdef/ifndef to exclude the WCF specific implementation
- Move WCF implementation into separate namespace