Manual steps for Gitlab CI pipeline

* Reduce default testcase to 2 nodes, add HA case.
* Adjust gen_matrix script for Travis/Gitlab CIs.
* Enable netchecker deploy foro gitlab CI.
* Sync other things from travis matrix and reorder them as build steps
  for pull requests, master branch, auto/manual.
* Do auto-step1 from part1 and manual step2,3 for branches/PRs.
* Do manual steps from part2, special for master merges.

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

tests/templates/inventory-gce.j2

@@ -1,6 +1,8 @@
 node1 ansible_ssh_host={{gce.instance_data[0].public_ip}}
 node2 ansible_ssh_host={{gce.instance_data[1].public_ip}}
+{% if mode is defined and mode in ["separate", "ha"] %}
 node3 ansible_ssh_host={{gce.instance_data[2].public_ip}}
+{% endif %}
 
 {% if mode is defined and mode == "separate" %}
 [kube-master]
@@ -11,19 +13,26 @@ node2
 
 [etcd]
 node3
-{% else %}
+{% elif mode is defined and mode == "ha" %}
 [kube-master]
 node1
 node2
 
 [kube-node]
-node1
-node2
 node3
 
 [etcd]
-node1
 node2
+node3
+{% else %}
+[kube-master]
+node1
+
+[kube-node]
+node2
+
+[etcd]
+node1
 {% endif %}
 
 [k8s-cluster:children]