win_scheduled_task: Added frequency: once and check_mode support (#22611)

* win_scheduled_task: Added frequency: once and check_mode support

This patch includes:
- Renamed `execute:` parameter to `executable:`
- Renamed `argument:` parameter to `arguments:`
- Implemented `frequency: once` support
- Implemented check_mode support
- Fix idempotency issue related to empty description
- Added integration tests

* Improve the integration test structure

I think this is a great way to test normal mode and check-mode from the same playbook.

* Small fixes after review

lib/ansible/modules/windows/win_scheduled_task.py

@@ -41,7 +41,6 @@ options:
   description:
     description:
       - The description for the scheduled task
-    required: false
   enabled:
     description:
       - Enable/disable the task
@@ -59,30 +58,27 @@ options:
   user:
     description:
       - User to run scheduled task as
-    required: false
-  execute:
+  executable:
     description:
       - Command the scheduled task should execute
-    required: false
-  argument:
+    aliases: [ execute ]
+  arguments:
     description:
       - Arguments to provide scheduled task action
-    required: false
+    aliases: [ argument ]
   frequency:
     description:
       - The frequency of the command, not idempotent
-    required: false
     choices:
+      - once
       - daily
       - weekly
   time:
     description:
       - Time to execute scheduled task, not idempotent
-    required: false
   days_of_week:
     description:
       - Days of the week to run a weekly task, not idempotent
-    required: false
   path:
     description:
       - Task folder in which this task will be stored
@@ -93,12 +89,13 @@ EXAMPLES = r'''
 # Create a scheduled task to open a command prompt
 - win_scheduled_task:
     name: TaskName
-    execute: cmd
-    frequency: daily
-    time: 9am
     description: open command prompt
+    executable: cmd
+    arguments: -opt1 -opt2
     path: example
-    enable: yes
+    time: 9am
+    frequency: daily
     state: present
+    enabled: yes
     user: SYSTEM
 '''