Adding RPM Packaging for CentOS 9 in Heka Insights

The Heka Insights Agent now supports RPM packaging for CentOS 9 and other Enterprise Linux 9-compatible distributions, allowing for native .rpm artifact installation using dnf and rpm ecosystem. This release addresses the need for a dedicated RPM packaging workflow, which is different from Debian-based systems. Operators can now build and install a native .rpm artifact, reducing compatibility risks with native libraries. The RPM installs the agent binary, systemd unit, and configuration example, and configuration is completed through the setup command. The service can be enabled and started with systemctl.