Coming from the discussion in OSPRH-20465, we identified a documentation gap that produces unclear assumptions about EDPM nodes timezone setting.

In https://docs.redhat.com/en/documentation/red_hat_openstack_services_on_openshift/18.0/html-single/planning_your_deployment/index chapter 4 (Planning provisioning for bare-metal data plane nodes) it says that unprovisioned nodes have to have their clocks set with UTC timezone.

While this is correct (we only support to provision new EDPM nodes with UTC) this leads to misunderstandings : EDPM nodes can have their clocks set to other timezones but UTC once they're provisioned, by using `edpm_timezone` ansible variable.