Add basic support for BIND 9 service

Merge request !29 (closed) / !39 (closed) adds basic support for services to Stork. It implements the Kea service and leaves BIND 9 service empty.

Add basic support for BIND 9.

• Implement detect running BIND 9 processes in agent.
• Store BIND 9 service information in database.
• Show BIND 9 service in Stork web ui.