Adding explicit install configuration for EL8 and EL9 systems

[kcaisley]

This pull request is meant to be done in partnership with The-OpenROAD-Project/OpenROAD#7997.

My goal here is to enable building on the most commonly used Enterprise Linux 8/9 systems, by explicitly naming AlmaLinux as a valid target. The NAME field of /etc/os-release across EL7, EL8, and EL9 system can take any of the following values:

"CentOS Linux" | "Red Hat Enterprise Linux Server" | "AlmaLinux" | "Rocky Linux" | "Red Hat Enterprise Linux"

So I first match against these, and then run one of the cases:

case "${elVersion}" in
    "7")
        # EL7 = RHEL 7 or CentOS 7
        if [[ "${option}" == "base" || "${option}" == "all" ]]; then
            _install_EL7_Packages
            _install_EL7_CleanUp
        fi
        ;;
    "8"|"9")
        # EL8/EL9 = RHEL, Rocky Linux, AlmaLinux, or CentOS 8+
        if [[ "${option}" == "base" || "${option}" == "all" ]]; then
            _install_EL8_EL9_Packages
            _install_EL8_EL9_CleanUp
        fi
        ;;
    *)
        echo "ERROR: Unsupported Enterprise Linux version: ${elVersion}" >&2
        exit 1
        ;;
esac

I fetch the correct .rpm version of klayout within the EL8/9 functions, and use dnf over yum for clarity.

[kcaisley]

One small thing which I'm not sure about, is if the cleanup functions need the rm -rf /var/lib/apt/lists/* line in them:

# Enterprise Linux 8/9 cleanup
_install_EL8_EL9_CleanUp() {
    dnf clean -y all
    rm -rf /var/lib/apt/lists/*
}

I included it here since _install_EL7_CleanUp() has the same, but by default I believe EL 7/8/9 distros don't have this directory present. Happy to add this, just wasn't sure if there was some reason to keep it.

[vvbandeira]

Please address comments above; otherwise, it looks good.
BTW, thanks for both PRs!

[vvbandeira]

@kcaisley there's a merge conflict