Download images as dependencies of roles

Pre download all required container images as roles' deps.
Drop unused flannel-server-helper images pre download.
Improve pods creation post-install test pre downloaded busybox.
Improve logs collection script with kubectl describe, fix sudo/etcd/weave
commands.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/dnsmasq/meta/main.yml

@@ -0,0 +1,5 @@
+---
+dependencies:
+  - role: download
+    file: "{{ downloads.dnsmasq }}"
+    when: not skip_dnsmasq|default(false)