[rdo-list] Remove periodic upgrade CI jobs from ci.centos

Hi, As discussed yesterday with Emilien, Sofer and Wes, we decided to remove the RDO upgrade ci jobs (periodic) from ci.centos.org since the workflow of the current tripleo upgrade is too big and slow. The duration of the jobs in the ci.centos infra take too much time, the jobs is hitting timeout or is running out of memory. The goal would be to put the effort on the upstream upgrade jobs with the new workflow: composable upgrade for Newton to Ocata. The workflow is light, and the ability of the use of the multinode save us from the timeout. We will implement the same workflow in tripleo-quickstart to be able to re-build new upgrade jobs on centos CI. Here is the discussion and the information: https://etherpad.openstack.org/p/tripleo-upgrade-jobs The review which drop the Upgrade jobs: https://review.rdoproject.org/r/#/c/4114/ The first start of the composable upgrade with tripleo-quickstart: https://review.openstack.org/410826