implemented loop pausing (#17289)

* implemented loop pausing

- added loop pause to changelog
- only pause between iterations, avoid 1st/last
- added example to docs

* fixed note placement

* else

* added docs for loop_control: label

lib/ansible/executor/task_executor.py

@@ -237,18 +237,27 @@ class TaskExecutor:
 
         loop_var = 'item'
         label = None
+        loop_pause = 0
         if self._task.loop_control:
             # the value may be 'None', so we still need to default it back to 'item' 
             loop_var = self._task.loop_control.loop_var or 'item'
             label = self._task.loop_control.label or ('{{' + loop_var + '}}')
+            loop_pause = self._task.loop_control.pause or 0
 
         if loop_var in task_vars:
             display.warning("The loop variable '%s' is already in use. You should set the `loop_var` value in the `loop_control` option for the task to something else to avoid variable collisions and unexpected behavior." % loop_var)
 
+        ran_once = False
         items = self._squash_items(items, loop_var, task_vars)
         for item in items:
             task_vars[loop_var] = item
 
+            # pause between loop iterations
+            if loop_pause and ran_once:
+                time.sleep(loop_pause)
+            else:
+                ran_once = True
+
             try:
                 tmp_task = self._task.copy(exclude_parent=True, exclude_tasks=True)
                 tmp_task._parent = self._task._parent