Add a Makefile rule in CMO to execute all the different rule that are used for verification and validation. Currenctly, some of them might not be at the right place, for example `check-assets` which is part of `generate` despite not being responsible of any generation. https://github.com/openshift/cluster-monitoring-operator/pull/1151/files#r629371735

DoD:

• Add a new rule in CMO to handle verification
• Add a CI job for this rule