Drop linux capabilities and rework users/groups

* Drop linux capabilities for unprivileged containerized
  worlkoads Kargo configures for deployments.
* Configure required securityContext/user/group/groups for kube
  components' static manifests, etcd, calico-rr and k8s apps,
  like dnsmasq daemonset.
* Rework cloud-init (etcd) users creation for CoreOS.
* Fix nologin paths, adjust defaults for addusers role and ensure
  supplementary groups membership added for users.
* Add netplug user for network plugins (yet unused by privileged
  networking containers though).
* Grant the kube and netplug users read access for etcd certs via
  the etcd certs group.
* Grant group read access to kube certs via the kube cert group.
* Remove priveleged mode for calico-rr and run it under its uid/gid
  and supplementary etcd_cert group.
* Adjust docs.
* Align cpu/memory limits and dropped caps with added rkt support
  for control plane.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

roles/kubernetes/preinstall/tasks/set_facts.yml

@@ -51,6 +51,3 @@
     etcd_container_bin_dir: "{% if etcd_after_v3 %}/usr/local/bin/{% else %}/{% endif %}"
 - set_fact:
     peer_with_calico_rr: "{{ 'calico-rr' in groups and groups['calico-rr']|length > 0 }}"
-
-- include: set_resolv_facts.yml
-  tags: [bootstrap-os, resolvconf, facts]