Revert: Force containers in k8s to run under root group

This reverts most of:
423df6618d

Since https://github.com/sclorg/redis-container/pull/62 is now shipped downstream

installer/roles/kubernetes/templates/deployment.yml.j2

@@ -116,8 +116,6 @@ spec:
         app: {{ kubernetes_deployment_name }}
     spec:
       serviceAccountName: {{ kubernetes_serviceaccount_name }}
-      securityContext:
-        fsGroup: 0
       terminationGracePeriodSeconds: 10
 {% if custom_venvs is defined %}
 {% set trusted_hosts = "" %}