This adds a `Convert Curves to Legacy Hair` operator. It converts all selected curves objects into new particle hair systems on their respective surface objects.
The purpose of the operator is to make the new curves sculpting tools useful even before all functionality is ported over.
{F12943100}
Currently, the generated hair system does not map exactly to the curves object for reasons that I don't fully understand. It's very close though. It might be a drawing issue or the hair strands are resampled somewhere else.
Questions:
* Should this always create a new particle system, or should it update an existing system? If it should update an existing system, should the mapping be by name?