Add oauth callback function for MSK/Managed_Kafka

[arnoldmr01]

• related: AIP-82: Add common messaging system providers #52712

What is this PR about?

This is a follow-up for #69000.
So far, KafkaBaseHook will add oauth_cb in configuration automatically based on the bootstrap.servers (from MSK or Managed_Kafka). This PR

• add an oauth_cb callback function for user to explicit config oauth_cb.
• add document about how to set up oauth_cb function.

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