Better handling for categoricalSorter in CategoricalRangeRule and FractionalRangeRule

**Is your feature request related to a problem? Please describe.**
In order to fix #70 and enable support for Deequ 2.x on #100, we performed a workaround (forcing the usage of a reference to the default `categorySorter`), instead of properly supporting this feature and exposing this argument to the Python API.

**Describe the solution you'd like**
Ideally, we wouldn't need to force the usage of the default `categorySorter` and expose this argument in the Python API to let users choose what they want.

**Describe alternatives you've considered**
Maybe we could implement an interface — similar to what we already do with ScalaFunction2 — that maps a Python function to the Scala counterpart. That said, I'm not sure how the handling of non-primitive types (such as `DistributionValue`) should happen on the Python side. Ideas are welcome here 😃