chore: use official apache kafka image for dockerfile

[Joel-hanson]

This pull request updates the Dockerfile to use the official apache/kafka:4.0.0 base image, streamlining the Kafka Connect container setup. The new approach removes the multi-stage build and manual Kafka installation, and now directly copies the connector JARs into the appropriate plugins directory. User and group setup is also simplified for better maintainability.

Container base image and setup:

• Switched the base image from a custom Alpine/IBM Java build to the official apache/kafka:4.0.0 image, eliminating manual Kafka installation steps.
• Simplified user and group creation by using addgroup and adduser commands, ensuring correct permissions for Kafka Connect.

Connector JAR management:

• Changed the connector JAR copy destination to /opt/kafka/plugins/ and removed the old /opt/connectors/ directory, aligning with Kafka Connect plugin conventions.
• Ensured the plugins and logs directories are created and owned by the correct user and group for secure operation.

Fixes #166

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules