Warn users about assets which will not be commissioned during the simulation

It is possible to define assets whose commission year is after the time horizon of the simulation. While I don't think we should forbid this, it is also possible that users could end up in this situation by accident (e.g. a typo), so we should warn if there are any assets that will not have an effect on the model, e.g. "Ignoring 3 assets with lifetimes after the last milestone year".