This commit renames the `types.hh` file to `brushes.hh` as an attempt to make brush implementations more independent and begin to unwind and remove much of the logic in `sculpt.cc`. As a first step, this moves the node mask calculation exposed for the plane brush into `plane.cc` and exposes the function header into `types.hh`. Pull Request: https://projects.blender.org/blender/blender/pulls/137020