Add allow_auto_create_topics to make automatic topic creation configurable

[kumaranvpl]

Description

We used to always create topics automatically and provided no way to make it configurable. This PR introduces a new variable called allow_auto_create_topics to make automatic topic creation configurable.
I have included a warning when allow_auto_create_topics is set to False because confluent-kafka-python backfires/crumbles terribly if it tries to access an non existent topic as mentioned here - confluentinc/confluent-kafka-python#1547.
There were few blocking calls in the __init__ method of Async Confluent Producer and Consumer. I have used run_in_executor to make them non-blocking.

Fixes #1486, #1363

Type of change

Please delete options that are not relevant.

• Documentation (typos, code examples, or any documentation updates)
• Bug fix (a non-breaking change that resolves an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a fix or feature that would disrupt existing functionality)
• This change requires a documentation update

Checklist

• My code adheres to the style guidelines of this project (scripts/lint.sh shows no errors)
• I have conducted a self-review of my own code
• I have made the necessary changes to the documentation
• My changes do not generate any new warnings
• I have added tests to validate the effectiveness of my fix or the functionality of my new feature
• Both new and existing unit tests pass successfully on my local environment by running scripts/test-cov.sh
• I have ensured that static analysis tests are passing by running scripts/static-analysis.sh
• I have included code examples to illustrate the modifications