[python-client] Support KeySharedPolicy in consumer configuration

Support for auto-hash and sticky-hash based policy (https://github.com/apache/pulsar/issues/4077) was added to cpp client (https://github.com/apache/pulsar/pull/7842) java (https://github.com/apache/pulsar/pull/5928) & go (https://github.com/apache/pulsar-client-go/pull/363) It would be great to have these changes ported to python client as well.

**Describe the solution you'd like**
Expose the ConsumerConfiguration::KeySharedPolicy and related setter/getter to Python client.