Feature/custom oauth callback class

[YuanShisong]

Type of change

Select the type of your PR

• Enhancement / new feature

Description

For kafka-connect there's a default OAUTH_CALLBACK_CLASS: sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler for SASL_MECHANISM: oauth. There need be a param for customize OauthCallbackHandler for customer who wants to use there own implemented OauthCallbackHandler.

[scholzj]

The type OAuth authentication is using the Strimzi OAuth library. I do not think there is any expectation to use it with some custom callback classes.

[scholzj]

Just to add to my previous comment:

• I don't think this PR really does anything from what you describe in the description.
• Should we support something like a custom OAuth implementation, it would need to be implemented for all compoenents - for example for the Bridge, Mirror Maker 2 etc.
• The right way to do it would probably start by writing a proposal (https://github.com/strimzi/proposals) for some type: custom authentication option rather than changing the Strimzi OAuth authentication.