Remove keycloak integration with Trino, OpenMetadata and Airflow

[avinashsingh77]

Looking at the difference in implementation mechanism and usability aspects of the applications, we have agreed on NOT integrating keycloak for SSO authentication.

This issue is mean to remove keycloak based authentication from Trino, Airflow, OpenMeteData and other applications in the platform.

We also need to setup(or ensure it is already setup) local users and document how it users can be added/removed using the same.