Removed dependency of murmurhash2

With confluent_kafka 2.1.1, the producer property partitioner is exposed on librdkafka.
With that, we can remove the dependency of the murmurhash2 lib, instead we will use librdkafka's

IMPORTANT: If you are upgrading to this new version, please run python3 -m pip install -r requirements.txt --upgrade

Initial production ready version

Version using confluent_kafka v1.9.2. In that python lib version the producer property "partitioner" on librdkafka isn't exposed, so a customer murmur2 partitioner needs to be implemented.