External configuration files (yaml)

[proycon]

The service configuration file (a python script) has always combined both host-specific settings as well as definition of the actual profiles. In production environments, however, changing the service configuration file may be less desireable and one might want to separate host-specific variable definitions from the rest, allowing to keep and install the service configuration python script as the delivered by the software provider.

I propose to add a mechanism to CLAM that simply allows loading of an external YAML configuration file on top of the existing service configuration file, setting and overriding any variables in the settings scope.

[proycon]

Implemented not as an override after all (wouldn't work well enough), but as a simple function call in the service configuration file, so it's something that needs to be explicitly enabled per webservice. The default template has been adapted accordingly.