Add option to use better hash function than default Java Object::hash
function to get better hashes which would be more equally spred over
the hash space and thus more equally over the Kafka partitions.
To preserve backward compatibility, previous Java `hashCode` function
is used a default.
Add Murmur3 hash function for computing hashes of the fields.
Murmur3 implementation is taken from from Infinispan project code base.
To allow users eventually use their own make `computePartition()`
protected so it can be overriden in the subclasses.
