Added 'k8s_deployed' fixture

Created a separate fixture for Kubernetes deployment.
Modified existing k8s related fixtures / tests so they
use it now and updated templates with k8s environments.

Also this patch includes few minor changes:

 * removed unused fixture 'deploy_openstack' which
   was a full copy of 'openstack_deployed' fixture;
 * removed unused modules imports;
 * fixed typos and docstrings.

Change-Id: Ic35551f3e52913cede753b92e7d5a81f54570b01
Reviewed-on: https://review.gerrithub.io/365234
Reviewed-by: <vrovachev@mirantis.com>
Reviewed-by: Dennis Dmitriev <dis.xcom@gmail.com>
Tested-by: Tatyanka Leontovich <tleontovich@mirantis.com>
diff --git a/tcp_tests/managers/k8s/__init__.py b/tcp_tests/managers/k8s/__init__.py
new file mode 100644
index 0000000..bd76aa7
--- /dev/null
+++ b/tcp_tests/managers/k8s/__init__.py
@@ -0,0 +1,20 @@
+#    Copyright 2017 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+
+import urllib3
+
+from tcp_tests.managers.k8s.cluster import K8sCluster
+
+__all__ = ['K8sCluster']
+
+urllib3.disable_warnings()  # Supress https insecure warning