cert-manager and cnpg operator can run on app node instead of infra node

[ardentperf]

based on the naming, it seems like the app node is supposed to be for things like pgbench or other test clients/apps and the operator, cert-manager, etc probably belongs on the infra node.

i can work on a fix (i think these should run on the infra node), but wanted to just report that i noticed the issue now in case anyone wanted to discuss

[gbartolini]

The operator can either run on the control-plane nodes or in the infra one. cert-manager in the infra one. pgbench in the app node, correct.