In preparation for #8079, new CI tests have to be added to Kokoro for
testing gRPC Python with Bazel.
python-dev has to installed so that Python.h headers are available for
building Cython code.
six is necessary for making these scripts cross compatible
between python 2.x and 3.x
Changes:
Add six to python_deps.include
Include python_deps.include to all Dockerfile templates in test directory
Include python_deps.include to all Dockerfile templates in stress_test directory
Include python_deps.include to all Dockerfile templates in interop_test directory
Replace print statements with print function calls (from futute..)
Replace .iteritems() with .items() wherever necessary
use six.moves to import BaseHTTPServer
Generate new dockerfiles using generate_projects.sh