Fix plugins (names, constants, FQCNs in examples) (#722)

* cobbler inventory: fix NAME

* oc transport: fix transport name

* Inventory plugins: fix plugin identifications

* Use FQCN in lookup plugin examples.

* Use FQCN in callback plugins.

* Add changelog fragment.

* Adjust documentation.

* Fix lookup plugin linting errors.

* Fix quotes.

(cherry picked from commit ea21341686)

plugins/inventory/virtualbox.py

@@ -19,7 +19,7 @@ DOCUMENTATION = '''
         plugin:
             description: token that ensures this is a source file for the 'virtualbox' plugin
             required: True
-            choices: ['virtualbox']
+            choices: ['virtualbox', 'community.general.virtualbox']
         running_only:
             description: toggles showing all vms vs only those currently running
             type: boolean
@@ -38,7 +38,7 @@ DOCUMENTATION = '''
 EXAMPLES = '''
 # file must be named vbox.yaml or vbox.yml
 simple_config_file:
-    plugin: virtualbox
+    plugin: community.general.virtualbox
     settings_password_file: /etc/virtulbox/secrets
     query:
       logged_in_users: /VirtualBox/GuestInfo/OS/LoggedInUsersList
@@ -46,7 +46,7 @@ simple_config_file:
       ansible_connection: ('indows' in vbox_Guest_OS)|ternary('winrm', 'ssh')
 
 # add hosts (all match with minishift vm) to the group container if any of the vms are in ansible_inventory'
-plugin: virtualbox
+plugin: community.general.virtualbox
 groups:
   container: "'minis' in (inventory_hostname)"
 '''