Adding env_setup folder and initial setup script.

Python 3 virtualenv setup and moves CIPD files from
https://pigweed.googlesource.com/infra/buildtools.

Change-Id: I0d0d8dfc2e80d9dadc80158201e71cda5c7a393b
diff --git a/.gitignore b/.gitignore
index da67e50..921e5b5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,7 +13,8 @@
 *.swp
 
 # Python
-python-env/
+python*-env/
+.python*-env/
 venv/
 *.pyc
 *.egg/