create and push docker image to zalando registry

[lotharschulz]

use delivery.yaml and use new cd platform

[lotharschulz]

part of #55

[lotharschulz]

Build triggered by 19d3d06 failed with

2017-06-26T21:19:27.878454923Z   File "/workspace/python/test_delete_instuck_progress.py", line 28, in test_drop_outdated_inprogress_file
2017-06-26T21:19:27.87847247Z      with tf.TemporaryDirectory() as tmp_dir:

Maybe python environment does not meet >3.4 ( https://docs.python.org/3.4/library/tempfile.html#tempfile.TemporaryDirectory)

[lotharschulz]

e7ac1b0 verified python 2.7.x instead of 3.x:

...
+ python --version
Python 2.7.12
+ nosetests -w python
...

[lotharschulz]

c897dc0 fails with

+ python --version
Python 3.5.2
+ pip install --upgrade pip
Traceback (most recent call last):
 File "/usr/bin/pip", line 9, in <module>
   from pip import main

most likely

pip install --upgrade pip

is not needed anymore

[lotharschulz]

docker push failed with tag invalid: tag already exists

[lotharschulz]

#72 merged and ghe-backup-automata & ghe-backup-bus image successfully deployed to pierone.