Managing configuration

[julienw]

Currently we manage configuration using a ConfigService that takes its values either from the command line and/or a configuration file.

But we'll want to expose configurations to the user through a web interface. Moreover some configuration might be dynamic (eg: door lock's codes, which luminosities mean day and night). So it would be better to expose them through the Getter/Setter (or whatever we come up with the decentralised taxonomy) with a special type: Config (a normal Getter/Setter could have a type User). Maybe the type could be a Tag instead.