When changing scenarios, Job related variables are not properly reset/initialized

[Fabulani]

When the scenario is changed by manipulating the selected_flexibility, Jobs don't reset (and keep their status), and Job queues keep their values.

If we for example do the following transition:

flexibility0 -> flexibility1 -> flexibility0

The scenario flexibility0 will have 6 Jobs initialized in MQTT, instead of the desired 3. This happens because in the Initialize state, the Job queue is not being reset to initial values, and on top of that we create 3 new Jobs.

The solution is to properly set up the Initialize and Shutdown states to make sure that Scenarios are being loaded in a desired state.