Optimize models updates

In QQEM data models are mostly reseted (beginResetModel() and endResetModel()) while they should only be partially updated. One place where this affects usability is when node has a lot of properties and you want to move the last property to first (select settings icon on top-right corner of properties view). Every move will reset the properties model, so you need to scroll down after every move.

There are many places where this could be done, but in this ticket do it for the most obvious ones and where model reseting causes issues.