refactor(kitchen): prefer kitchen.yml to .kitchen.yml

* Quoting from https://kitchen.ci/docs/getting-started/kitchen-yml/:
  - As of test-kitchen 1.21.0, we now prefer `kitchen.yml` over `.kitchen.yml`.
  - This preference applies to `kitchen.local.yml` as well.
  - This is backward compatible so the dot versions continue to work.

kitchen.yml

@@ -0,0 +1,26 @@
+---
+driver:
+  name: vagrant
+  network:
+    - ["private_network", { ip: "192.168.33.33" }]
+
+provisioner:
+  name: salt_solo
+  formula: postgres
+  pillars-from-files:
+    postgres.sls: pillar.example
+  pillars:
+    top.sls:
+      base:
+        "*":
+          - postgres
+  state_top:
+    base:
+      "*":
+        - postgres
+
+platforms:
+  - name: ubuntu-14.04
+
+suites:
+  - name: default