Use playbook callbacks for adhoc commands too

This makes adhoc mirror playbook callback functionality by running a
callback before and after all tasks have run. Adhoc commands now call:

- v2_playbook_on_start
- v2_playbook_on_stats

NOTE: When v2_playbook_on_start is called, a dummy playbook is provided
that says its _file_name is __adhoc_playbook__. All callback plugins
that provide v2_playbook_on_start access the _file_name attribute, so
this should maintain backward compatibility when those plugins are
called with adhoc commands even though they would not have been called
previously. The adhoc play is also added to _entries for any private
callback plugins that might be using this callback.

lib/ansible/cli/adhoc.py

@@ -28,6 +28,7 @@ from ansible.errors import AnsibleError, AnsibleOptionsError
 from ansible.executor.task_queue_manager import TaskQueueManager
 from ansible.module_utils._text import to_text
 from ansible.parsing.splitter import parse_kv
+from ansible.playbook import Playbook
 from ansible.playbook.play import Play
 from ansible.plugins.loader import get_all_plugin_loaders
 
@@ -145,6 +146,11 @@ class AdHocCLI(CLI):
         play_ds = self._play_ds(pattern, self.options.seconds, self.options.poll_interval)
         play = Play().load(play_ds, variable_manager=variable_manager, loader=loader)
 
+        # used in start callback
+        playbook = Playbook(loader)
+        playbook._entries.append(play)
+        playbook._file_name = '__adhoc_playbook__'
+
         if self.callback:
             cb = self.callback
         elif self.options.one_line:
@@ -175,7 +181,11 @@ class AdHocCLI(CLI):
                 run_tree=run_tree,
             )
 
+            self._tqm.send_callback('v2_playbook_on_start', playbook)
+
             result = self._tqm.run(play)
+
+            self._tqm.send_callback('v2_playbook_on_stats', self._tqm._stats)
         finally:
             if self._tqm:
                 self._tqm.cleanup()