Add support for oauthbearer_token_refresh_cb events

[GaryWilber]

• Add support for the oauthbearer_token_refresh_cb callback, which will emit a oauthbearer.tokenrefresh event. This will be called when librdkafka wants us to call setOauthBearerToken. It will be based on the lifetime of the token
• Add optional lifetime parameter to setOauthBearerToken and refreshOauthBearerToken

Based on how https://github.com/confluentinc/confluent-kafka-javascript does it