Use createrepo_c to replace createrepo

[happyaron]

createrepo_c is the C re-implementation of createrepo.

createrepo itself is written in Python, when the --update option is used all nodes are read into RAM, which is affected by the inefficiency of Python's objects storage. This is the reason of the high memory usage of genpkgmetadata process, affecting mysql, grafana, influxdata, kubernets and other yum-sync based repos.

createrepo_c is first included in Debian bullseye, replacing the createrepo package in buster.