Rename from community.kubernetes to kubernetes.core (#6)

* Rename from community.kubernetes to kubernetes.core

This goes through and renames community.kubernetes to kubernetes.core.
Most of this was generated from the downstream build script that was
used on the community repository, plus whatever hand edits I could find
that were needed.

The downstream build and test process has also been removed as this
repository is now the downstream repository.

* Fix CONTRIBUTING.md

plugins/inventory/k8s.py

@@ -23,7 +23,7 @@ DOCUMENTATION = '''
       plugin:
          description: token that ensures this is a source file for the 'k8s' plugin.
          required: True
-         choices: ['community.kubernetes.k8s', 'k8s']
+         choices: ['kubernetes.core.k8s', 'k8s']
       connections:
           description:
           - Optional list of cluster connection settings. If no connections are provided, the default
@@ -95,20 +95,20 @@ EXAMPLES = '''
 # File must be named k8s.yaml or k8s.yml
 
 # Authenticate with token, and return all pods and services for all namespaces
-plugin: community.kubernetes.k8s
+plugin: kubernetes.core.k8s
 connections:
   - host: https://192.168.64.4:8443
     api_key: xxxxxxxxxxxxxxxx
     validate_certs: false
 
 # Use default config (~/.kube/config) file and active context, and return objects for a specific namespace
-plugin: community.kubernetes.k8s
+plugin: kubernetes.core.k8s
 connections:
   - namespaces:
     - testing
 
 # Use a custom config file, and a specific context.
-plugin: community.kubernetes.k8s
+plugin: kubernetes.core.k8s
 connections:
   - kubeconfig: /path/to/config
     context: 'awx/192-168-64-4:8443/developer'
@@ -117,7 +117,7 @@ connections:
 import json
 
 from ansible.errors import AnsibleError
-from ansible_collections.community.kubernetes.plugins.module_utils.common import K8sAnsibleMixin, HAS_K8S_MODULE_HELPER, k8s_import_exception, get_api_client
+from ansible_collections.kubernetes.core.plugins.module_utils.common import K8sAnsibleMixin, HAS_K8S_MODULE_HELPER, k8s_import_exception, get_api_client
 from ansible.plugins.inventory import BaseInventoryPlugin, Constructable, Cacheable
 
 try:
@@ -142,9 +142,9 @@ class K8sInventoryException(Exception):
 
 
 class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable, K8sAnsibleMixin):
-    NAME = 'community.kubernetes.k8s'
+    NAME = 'kubernetes.core.k8s'
 
-    connection_plugin = 'community.kubernetes.kubectl'
+    connection_plugin = 'kubernetes.core.kubectl'
     transport = 'kubectl'
 
     def parse(self, inventory, loader, path, cache=True):