Add etcd proxy support

* Enforce a etcd-proxy role to a k8s-cluster group members. This
provides an HA layout for all of the k8s cluster internal clients.
* Proxies to be run on each node in the group as a separate etcd
instances with a readwrite proxy mode and listen the given endpoint,
which is either the access_ip:2379 or the localhost:2379.
* A notion for the 'kube_etcd_multiaccess' is: ignore endpoints and
loadbalancers and use the etcd members IPs as a comma-separated
list. Otherwise, clients shall use the local endpoint provided by a
etcd-proxy instances on each etcd node. A Netwroking plugins always
use that access mode.
* Fix apiserver's etcd servers args to use the etcd_access_endpoint.
* Fix networking plugins flannel/calico to use the etcd_endpoint.
* Fix name env var for non masters to be set as well.
* Fix etcd_client_url was not used anywhere and other etcd_* facts
evaluation was duplicated in a few places.
* Define proxy modes only in the env file, if not a master. Del
an automatic proxy mode decisions for etcd nodes in init/unit scripts.
* Use Wants= instead of Requires= as "This is the recommended way to
hook start-up of one unit to the start-up of another unit"
* Make apiserver/calico Wants= etcd-proxy to keep it always up

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Co-authored-by: Matthew Mosesohn <mmosesohn@mirantis.com>

roles/etcd/templates/deb-etcd-docker.initd.j2

@@ -16,23 +16,16 @@ PATH=/sbin:/usr/sbin:/bin/:/usr/bin
 DESC="etcd k/v store"
 NAME=etcd
 DAEMON={{ docker_bin_dir | default("/usr/bin") }}/docker
-{% if is_etcd_master %}
 DAEMON_ARGS='--restart=always --env-file=/etc/etcd.env \
 --net=host \
 -v /usr/share/ca-certificates/:/etc/ssl/certs:ro \
 -v /var/lib/etcd:/var/lib/etcd:rw \
---name={{ etcd_member_name | default("etcd-proxy") }} \
+--name={{ etcd_member_name | default("etcd") }} \
 {{ etcd_image_repo }}:{{ etcd_image_tag }} \
 {% if etcd_after_v3 %}
-{{ etcd_container_bin_dir }}etcd \
-{% endif %}
-{% if is_etcd_master %}
---proxy off
-{% else %}
---proxy on
+{{ etcd_container_bin_dir }}etcd
 {% endif %}'
 
-
 SCRIPTNAME=/etc/init.d/$NAME
 DAEMON_USER=etcd
 STOP_SCHEDULE="${STOP_SCHEDULE:-QUIT/5/TERM/5/KILL/5}"
@@ -41,9 +34,6 @@ PID=/var/run/etcd.pid
 # Exit if the binary is not present
 [ -x "$DAEMON" ] || exit 0
 
-# Read configuration variable file if it is present
-[ -f /etc/etcd.env ] && . /etc/etcd.env
-
 # Define LSB log_* functions.
 # Depend on lsb-base (>= 3.2-14) to ensure that this file is present
 # and status_of_proc is working.