Feat: implementing config key containing many types accepted by kafka

[YlanzinhoY]

What

Looking at the configmap, we always have to literally pass a key that is valid for Kafka in string format, that said, why not create a type that contains several constants that will be accepted keys for Kafka?
// Instead of this
c, err :=kafka.NewConsumer(&kafka.ConfigMap{
"bootstrap.servers": "localhost",
"group.id": "myGroup",
"auto.offset.reset": "earliest",
})

//use this
c, err := kafka.NewConsumer(&kafka.ConfigMap{
kafka.BootstrapServers": "localhost",
kafka.GroupId: "myGroup",
kafka.AutoOffsetReset: "earliest",
})

both ways will work in kafka according to the tests I did, so we maintain compatibility both for those who want to write literally and for those who like to have a typing that shows all possible keys.

Checklist

• Contains customer facing changes? Including API/behavior changes
• Did you add sufficient unit test and/or integration test coverage for this PR?
  References

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JIRA:
None

Test & Review

I tested it with unit tests and modified some small tests

[Copilot]

Pull Request Overview

This PR introduces a new ConfigKey type and associated constants to provide typed configuration keys for Kafka while maintaining backwards compatibility with string literals. Key changes include:

• Converting configuration map keys from string to ConfigKey in multiple modules.
• Updating tests and helper functions to work with the new type.
• Introducing a new file for Kafka configuration key constants.

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
kafkatest/go_verifiable_producer/go_verifiable_producer.go	Converted literal keys to ConfigKey in the producer test
kafkatest/go_verifiable_consumer/go_verifiable_consumer.go	Converted literal keys to ConfigKey in the consumer test
kafka/testhelpers_test.go	Updated key lookup and deletion to use ConfigKey
kafka/consumer_test.go	Replaced string keys with constants for improved type-safety
kafka/config_key.go	Introduced a new file with ConfigKey constants for all accepted Kafka keys
kafka/config.go	Updated ConfigMap type and key conversion logic
README.md	Updated examples to illustrate the new ConfigKey usage

Comments suppressed due to low confidence (1)

kafka/config_key.go:4

• [nitpick] Consider renaming 'AutoOffSetReset' to 'AutoOffsetReset' to ensure consistent naming conventions across configuration constants.

AutoOffSetReset                              ConfigKey = "auto.offset.reset"