CPAlgorithms: better default settings for OverlapRemoval

The Overlap Removal (OR) config block has a boolean option addToAllSelections. Users can have a hard time figuring out the proper settings of the config block and this option in particular. In our notes on handling multiple object selections, we show how to set up multiple instances of OR: in those cases, one certainly doesn't want to add both OR selections to all objects! On the other hand, with only one OR setup, one would like to not have to remember to add passesOR_%SYS% everywhere...

In this MR, I change the addToAllSelections default value to None, which will make it be autoconfigured depending on how many OR algorithms have been registered with the ConfigAccumulator. This solves a lot of worries user-side. Experts can still set that option to True/False to obtain whatever configurations they like.