Bug 1089464 - [Smart Screen][Home]Launch card directly from smart home

To be able launch app from Smart Home directly, with some more unit tests also.

https://bugzilla.mozilla.org/show_bug.cgi?id=1089464
Just a proposal: The implementation for this in System App is `this.CLASS_NAME + '_' + _id`, which `CLASS_NAME` is a pre-defined string name and `_id` is a static counter. But we can discuss about this.