Test automation for dns cli plugin secret-generation command

[averevki]

Summary

Add test for DNS Operator dns cli plugin kubectl-dns secret-generation command.

Additional context

Example of the command usage:

kubectl-dns secret-generation --name kubeconfig-secret-$(whoami) -c default/api-kua-hub-local-net:6443/admin -n kuadrant-system -a coredns

kubectl-dns plugin can be downloaded from dns-operator releases page, or built from the main branch using makefile