Use cmake 3.x to build LOFAR
We want to upgrade cmake to >=3.19 to use newer features in !1003. Upgrading cmake makes it more future proof in general as well.
This work upgrades cmake in the Docker CI images. On cbm206 and head02.cep4, a newer cmake is deployed manually. Ticket https://support.astron.nl/jira/browse/ROADMT-1121 aims to do so properly through Ansible.
Edited by Jan David Mol