EL9: remove chkconfig package in base configuration

[jouvin]

chkconfig is a deprecated package in EL9. It would be good to remove it from the default OS configuration. A failure to do it during 24.10.0-rc4 failed (quattor/release#365). 2 issues must be solved first:

• ncm-named must be replaced by ncm-metaconfig as it relies on chkconfig command and is considered obsolete (Configuration modules that can be replaced by usage of metaconfig configuration-modules-core#434)
• ncm-systemd must be fixed not to require chkconfig command if the legacy/chkconfig mode is not configured (ncm-systemd 23.6.0: remove chkconfig requirement if legacy mode (chkconfig) is not used configuration-modules-core#1731)

Once the issues are fixed, it is enough to define variable OS_INSTALL_CHKCONFIG=false by default config/core/base) and to uncomment the deprecation warning in rpms/base.