Make Kibble a package

[turbaszek]

This commit refactors the code base to create an installable
kibble application. In this way we will be able to do:

pip install .
# or once released:
pip install apache-kibble

and then

➜ kibble --help
Help hello to kibble!

Related to: #64
Closes: #37

What has happened in this PR:

• move api/ and setup/ under kibble/ directory
• adjust all imports and files paths
• create kibble/settings.py to store common constants
• create kibble/version.py with version information
• create setup.py with requirements and remove requirements.txt file
• create kibble/__main__.py as a starting point for kibble application - that's what will be invoked when users do kibble --help
• adjust docker file and docker-compose to make everything works

[michalslowikowski00]

LGTM 🎸