Populate database with reproducible configuration

[oxzi]

In the current duality of icinga-notifications and icinga-notifications-web, all configuration is done through the web interface, which serializes it into the SQL database. While this clicking-centered approach might be suitable in most cases, it has its downsides when it comes to automation, e.g., for testing or whole Icinga monitoring stack configuration.

This issue was raised in discussions where to store configuration, being addressed in #132.

That's why I would suggest adding another command line program to populate the database from a configuration file.