Add support for OAuthbearer auth mechanism

[cbcoutinho]

Checklist

• I have included information about relevant versions
• I have verified that the issue persists when using the master branch of Faust.

Steps to reproduce

OAuth 2.0 support would allow faust streaming apps to be used in Confluent Cloud clusters configured with custom identity pools.

For comparison, the Confluent python library supports OAuth 2 by providing a callback to the consumer/producer __init__.

https://docs.confluent.io/platform/current/clients/confluent-kafka-python/html/index.html#kafka-client-configuration

Expected behavior

It would be great to be able to utilize Faust with clusters that require integration with external identity providers.

[wbarnha]

We use aiokafka but it seems to be possible to use OAuth from the existing issue in aio-libs/aiokafka#691.