Add back python2-setuptools

This adds back a python 2 version of setuptools but with all dependencies vendored
(the upstream default..). To allow users to install Python 2 packages we no longer
have in the repo etc which should help them transitioning.

This also adds conflicts between py2/3 setuptools because of the esy_install rename.

See #4993

mingw-w64-python2-setuptools/0004-dont-execute-msvc.patch

@@ -0,0 +1,12 @@
+--- setuptools-27.3.0/setuptools/monkey.py.orig	2016-09-23 11:38:23.517707200 +0300
++++ setuptools-27.3.0/setuptools/monkey.py	2016-09-23 11:39:40.362333800 +0300
+@@ -90,7 +90,8 @@
+             setuptools.extension.Extension
+         )
+ 
+-    patch_for_msvc_specialized_compiler()
++    if not 'GCC' in sys.version:
++        patch_for_msvc_specialized_compiler()
+ 
+ 
+ def _patch_distribution_metadata_write_pkg_file():