Rename `distillation` in RssMaker used for force-based filtering

[YuanbinLiu]

In the current RssMaker YAML file, the distillation flag is currently used with force_max to filter out structures during training. However, the term distillation is sort of misleading. Rename it to force_filtering or a similar, more descriptive name in the next release.

[JaGeo]

Please go ahead and rename it. With the current user numbers, we can still make such changes rather freely.