Remove Guava dependency

[mkobit]

It is unused and forces consumers to deal with compatibility concerns.

Summary

Removes Guava as a dependency.

Pull Request (PR) Checklist

Documentation

• [x] Documentation in README.md or Wiki updated
• [x] Update Release Notes if applicable -- collaborator-access only

Code Review

• [x] Self code review -- take another pass through the changes yourself
• [x] Completed all relevant TODOs, or call them out in the PR comments

Tests

• [x] All tests passes - (./mvn verify)

[mkobit]

build failure looks to come from Cassandra binary distribution not being found, going to look at fixing the script

[hhandoko]

Thanks for your contribution!