Move CI vars out of gitlab and into var files (#1808)

tests/files/centos7-flannel-addons.yml

@@ -0,0 +1,14 @@
+# Instance settings
+cloud_image: centos-7
+cloud_region: us-west1-a
+cloud_machine_type: "n1-standard-1"
+mode: default
+
+# Deployment settings
+kube_network_plugin: flannel
+helm_enabled: true
+istio_enabled: true
+efk_enabled: true
+deploy_netchecker: true
+kubedns_min_replicas: 1
+cloud_provider: gce