kubernetes/preinstall: dns setting cleanup(dhclient, resolvconf)

We use a lot of facts where variables are enough, and format too early,
which prevent reusing the variables in different contexts.

- Moves set_fact variables to the vars directory, remove unnecessary
 intermediate variables, and render them at usage sites to only do logic
 on native Ansible/Jinja lists.
- Use defaults/ rather than default filters for several variables.

roles/kubernetes/preinstall/defaults/main.yml

@@ -2,6 +2,9 @@
 # Set to true to allow pre-checks to fail and continue deployment
 ignore_assert_errors: false
 
+nameservers: []
+cloud_resolver: []
+disable_host_nameservers: false
 epel_enabled: false
 # Kubespray sets this to true after clusterDNS is running to apply changes to the host resolv.conf
 dns_late: false