Prepare python package to integrate it in xtesting docker

Prepare python package to integrate it in xtesting docker

- creation of entrypoint
- include templates in the package
- complete requirements

Open question for integration python reviewers:
- I was not able with the MANIFEST to use the template directory  until
I put it in the package tree. I am not sure it is very nice..
Maybe it is not the right way, we could simply copy the templates in the
docker rather than including them as part of the python package..

Note: I retested the ubuntu16 (onboarding/deployment/instantiation) on
the Daily Master

Issue-ID: TEST-258

Signed-off-by: mrichomme <morgan.richomme@orange.com>
Change-Id: I26f3e959b9c5e341ab197a6c519ca87e31921921
Signed-off-by: mrichomme <morgan.richomme@orange.com>