[SCORING] Improve lowEndDevice score

[apoichet]

CONTEXT :

At the moment, we return a simple boolean to check if a device is a low end device or not. But it's not enough. Consider that user of the plugin would decide if the device is effectively a low end device or not. We should give them something like an advice or recommandations that they can override.

TODO :

Return a business object with more information concerning eco mode =>low end device score with state or detailed information.