Make SlotHash utility methods public

[ze]

Feature Request

Is your feature request related to a problem? Please describe

I have a use case where I want to use the exact logic in SlotHash.java#partition, but it is package private. This method is useful for doing as it says, partitioning keys by a slot for whatever workload.

Describe the solution you'd like

Make the method public. It may be worthwhile to make getSlots public as well. I haven't used it, but it could be useful.

Describe alternatives you've considered

I copied over the functions to their own utility class and linked to the source, so that is an alternative. It's extra code we need to own though. I don't think any meaningful alternatives exist.

Teachability, Documentation, Adoption, Migration Strategy

Not much really needs to be done. The javadocs are already there.