EADK (StdLib, AppPkg, StdLibPrivateInternalFiles): Python Beta Release.

Clean up and clearly differentiate required and optional items in configuration files.
Enable the system command and synchronize configuration options between all CPU architectures.
Replace the UEFI_ENV macro with UEFI_C_SOURCE to align with Linux and Posix conventions.
Update copyrights and versions and make minor cosmetic enhancements to files.
Fix compiler-specific build errors.
Add Python-specific ReadMe file.

Signed-off-by: darylm503
Reviewed-by: geekboy15a
Reviewed-by: jljusten
Reviewed-by: leegrosenbaum
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13119 6f19259b-4bc3-4df7-8a09-765794883524