ci:Support Rocky Linux

[mbolla22]

Add Support for Rocky Linux 9 in CI/CD Workflows

This update introduces support for Rocky Linux 9 in the CI/CD workflows for building, testing, and publishing Docker container images. The following changes were made:

Docker Build Workflow (ci_build_docker_runner.yml)

• Added rocky9 to the matrix strategy for Dockerfile builds.
• Ensures that a Docker image for Rocky Linux 9 is built and pushed to the GitHub Container Registry (ghcr.io).

Testing Workflow (testing.yml)

• Included rocky9 in the platforms list for Molecule tests.
• Ensures that the testing pipeline validates the infrastructure agent package on Rocky Linux 9.

Platform Preparation Script (prepare_platform.sh)

• Verified that rocky9 is included in the available_platforms array.
• Ensured that platform-specific configurations (e.g., Python interpreter groups) are correctly applied to Rocky Linux 9.

Dockerfile for Rocky Linux 9

• Created a new Dockerfile (rocky9) based on the Rocky Linux 9 base image.
• Configured the Dockerfile to install necessary dependencies and include a fake systemctl for containerized environments.

These changes ensure that Rocky Linux 9 is fully integrated into the build, test, and deployment pipelines, aligning with the project's goal of supporting a wide range of Linux distributions.