[kolla] Feedback request: removing OracleLinux support

Hi, We discussed during the kolla virtual PTG [1] the option of removing support for Oracle Linux, as a way to improve the long term sustainability of the project. Since (from afar) OracleLinux is very similar to CentOS, it does not require too much maintenance, however it is non-zero and does consume CI resources. Contributors from Oracle left the community some time ago, and we do not generally see Oracle Linux in bug reports, so must assume it is not well used. We propose dropping support for OracleLinux in the Train cycle. If this will affect you and you would like to help maintain it, please get in touch. Thanks, Mark [1] https://etherpad.openstack.org/p/kolla-train-ptg