Replace openshift client with kubernetes client (#96)

* Replace openshift client with kubernetes client

This commit primarily just removes mentions of openshift from the docs
and updates the requirements. Most of the work to replace the client has
been done through the following commits:

edc48ee577
c214376cac
48c5170018
2b6a989cf9

* Add changelog fragment

* Update changelogs/fragments/96-replace-openshift-client.yaml

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

* Update plugins/modules/k8s.py

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

* Update plugins/modules/k8s_info.py

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

* Update plugins/modules/k8s_service.py

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

* Bump minimum kubernetes version to 12.0.0

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

plugins/doc_fragments/k8s_auth_options.py

@@ -24,7 +24,7 @@ options:
   kubeconfig:
     description:
     - Path to an existing Kubernetes config file. If not provided, and no other connection
-      options are provided, the openshift client will attempt to load the default
+      options are provided, the Kubernetes client will attempt to load the default
       configuration file from I(~/.kube/config). Can also be specified via K8S_AUTH_KUBECONFIG environment
       variable.
     type: path
@@ -110,9 +110,6 @@ options:
     - "The fix for this k8s python library is here: https://github.com/kubernetes-client/python-base/pull/169"
     type: bool
 notes:
-  - "The OpenShift Python client wraps the K8s Python client, providing full access to
-    all of the APIS and models available on both platforms. For API version details and
-    additional information visit https://github.com/openshift/openshift-restclient-python"
   - "To avoid SSL certificate validation errors when C(validate_certs) is I(True), the full
     certificate chain for the API server must be provided via C(ca_cert) or in the
     kubeconfig file."