Add count-min sketch

[jmalkin]

The C++ library offers a count-min sketch. The Java library should include a compatible implementation.

[geonove]

Hi there @jmalkin , I recently ported count-min sketch to Datasketches-go. I can do the same here, if you'd like you can assign this issue to me

[c-dickens]

@geonove I have assigned you.

[geonove]

@c-dickens, @jmalkin the PR is ready for review :)