Drop the support of BaseTools Python run from the freeze binary in Windows OS

["Gao, Liming" <liming.gao@intel.com>]

Hi, all
  Now, we are working to migrate BaseTools Python tool from Python27 to Python36. To reduce the migration effort, we will only verify BaseTools Python tool run from source. That means we will stop to support the freeze python tool as windows exe. In fact, we get the report that edk2-BaseTools-win32 doesn't work. We don't plan to fix it. If you still use the freeze python tool exe, please run BaseTools Python from source in Windows. Here is the step wiki https://github.com/tianocore/tianocore.github.io/wiki/Windows-systems Compile Tools section. After migrate to Python36, we will update wiki page to document Python36 step.

>From now, we will stop to freeze python tool, remove Edk2\BaseTools\Source\Python\Makefile, and stop update edk2-BaseTools-win32 github repo. And, I will reset edk2-BaseTools-win32 binary to match edk2 vUDK2018 tag. If you require the freeze python tool, you can maintain your step to freeze the python tool. Here is the link https://docs.python-guide.org/shipping/freezing/ to introduce the different freezing solutions.

Thanks
Liming