Update rke, kubectl and helm

This commit updates rke (implementing K8S 1.15.4), kubectl binary and
helm binary with tiller image:

rke             0.3.0
kubernetes      1.15.4
kubectl         1.15.4
helm            2.14.2
dashboard       2.0.0-beta4

Kubernetes dashboard is also updated to be compliant with the 1.15 K8S.

Note 1:
There is a new datalist to split rke only images from other K8S related
images.

Note 2:
El Alto recommendation cannot be fullfilled to the letter, because rke
does not have any release supporting 1.15.2 version of kubernetes (only
experimental).

Issue-ID: OOM-2122

Change-Id: I02cf0955158eca622bcac40ceed42588dbdd3499
Signed-off-by: Tomáš Levora <t.levora@partner.samsung.com>
Signed-off-by: Petr Ospalý <p.ospaly@partner.samsung.com>
Signed-off-by: Bartek Grzybowski <b.grzybowski@partner.samsung.com>
diff --git a/ansible/group_vars/infrastructure.yml b/ansible/group_vars/infrastructure.yml
index fec242d..dd07373 100755
--- a/ansible/group_vars/infrastructure.yml
+++ b/ansible/group_vars/infrastructure.yml
@@ -19,7 +19,7 @@
   "{{ simulated_hosts.http + simulated_hosts.nexus }}"
 populate_nexus: false
 helm_bin_dir: /usr/local/bin
-helm_version: v2.12.3
+helm_version: v2.14.2
 rancher_server_image: rancher/server:v1.6.22
 vnc_server_image: consol/ubuntu-icewm-vnc:1.4.0
 nexus3_image: sonatype/nexus3:3.15.2