Report if transition history ends up in the electroweak minimum at T = 0

[lisabiermann]

It would be good to add a flag to the transition_history to report whether the point is found to end up in the electroweak minimum at zero temperature (whose existence is checked and required for by default). This at the moment has to be deduced from the information of the traced phases and the transition_history column.

Thanks to @cborschensky for making this suggestion!