[Feature request] Enable AUTO_CONSUME

It doesn't seem like the python client supports auto consume. This does however seem to be the case for the java client as documented [here](https://pulsar.apache.org/docs/2.10.x/schema-understand/). It would be useful to have for the python client as well. It seems like there is already some C++ code in the repo related to AUTO_CONSUME, [here](https://github.com/apache/pulsar-client-python/blob/c69cf1f3238f751b48fe8994801fdd54c02eb21c/src/enums.cc#L110).

Read src/enums.cc around line 110 and compare the Python client's capabilities with the Java client's AUTO_CONSUME behavior in the linked documentation. Determine the implementation scope and any needed validation; done means Python users can use AUTO_CONSUME consistently with the documented Java behavior.

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