Fix the pretty-printing of (core|nodelocal)dns (#11723)

When using
dns_upstream_forward_extra_opts:
  prefer_udp: "" # the option as no value so use empty string to just
                 # put the key

This is rendered in the dns configmap as ($ for end-of-line)

...
  prefer_udp $
...

Note the trailing space.
This triggers https://github.com/kubernetes/kubernetes/issues/36222,
which makes the configmap hardly readable when editing them manually or
simply putting them in a yaml file for inspection.

Trim the concatenation of option + value to get rid of any trailing
space.

Co-authored-by: Max Gautier <mg@max.gautier.name>

roles/kubernetes-apps/ansible/templates/coredns-config.yml.j2

@@ -73,7 +73,9 @@ data:
           max_concurrent 1000
 {% if dns_upstream_forward_extra_opts is defined %}
 {% for optname, optvalue in dns_upstream_forward_extra_opts.items() %}
-          {{ optname }} {{ optvalue }}
+          {{ (optname ~ ' ' ~ optvalue) | trim }}
+          {# do not add a trailing space when optvalue == ''
+             workaround for: https://github.com/kubernetes/kubernetes/issues/36222 #}
 {% endfor %}
 {% endif %}
         }

roles/kubernetes-apps/ansible/templates/nodelocaldns-config.yml.j2

@@ -82,7 +82,9 @@ data:
         bind {{ nodelocaldns_ip }}
         forward . {{ upstreamForwardTarget }}{% if dns_upstream_forward_extra_opts is defined %} {
 {% for optname, optvalue in dns_upstream_forward_extra_opts.items() %}
-          {{ optname }} {{ optvalue }}
+          {{ (optname ~ ' ' ~ optvalue) | trim }}
+          {# do not add a trailing space when optvalue == ''
+             workaround for: https://github.com/kubernetes/kubernetes/issues/36222 #}
 {% endfor %}
         }{% endif %}
 
@@ -164,7 +166,9 @@ data:
         bind {{ nodelocaldns_ip }}
         forward . {{ upstreamForwardTarget }}{% if dns_upstream_forward_extra_opts is defined %} {
 {% for optname, optvalue in dns_upstream_forward_extra_opts.items() %}
-          {{ optname }} {{ optvalue }}
+          {{ (optname ~ ' ' ~ optvalue) | trim }}
+          {# do not add a trailing space when optvalue == ''
+             workaround for: https://github.com/kubernetes/kubernetes/issues/36222 #}
 {% endfor %}
         }{% endif %}