Fix Packaging Errors

[Elliesaur]

Currently while packaging the release it will fail complaining of not having external symbols.

Example:

UATHelper: Packaging (Windows): Module.Launch.cpp.obj : error LNK2019: unresolved external symbol "bool GIsGameAgnosticExe" (?GIsGameAgnosticExe@@3_NA) referenced in function "void __cdecl LaunchFixGameNameCase(void)" (?LaunchFixGameNameCase@@YAXXZ)
UATHelper: Packaging (Windows): Module.Core.9_of_20.cpp.obj : error LNK2001: unresolved external symbol "bool GIsGameAgnosticExe" (?GIsGameAgnosticExe@@3_NA)
UATHelper: Packaging (Windows): Module.AutomationWorker.cpp.obj : error LNK2001: unresolved external symbol "wchar_t * GInternalProjectName" (?GInternalProjectName@@3PA_WA)

This fix resolves these by implementing the primary game module on Pal module instead of commenting it out like it is currently.

There has also been documentation added to resolve probably unintended building with VS 2019 build tools.

This fix has been tested by:

• Following readme to a point.
• Building the project in VS after generating solution files first from the uproject.
• Opening the editor.
• Packaging for shipping.