**- Why I did it**
Install all host services and their data files in package format rather than file-by-file
**- How I did it**
- Create sonic-host-services Python wheel package, currently including procdockerstatsd
- Also add the framework for unit tests by adding one simple procdockerstatsd test case
- Create sonic-host-services-data Debian package which is responsible for installing the related systemd unit files to control the services in the Python wheel. This package will also be responsible for installing any Jinja2 templates and other data files needed by the host services.
