Clean up module documentation (#36909)

* Clean up module documentation

This PR includes:
- Removal of `default: None` (and variations)
- Removal of `required: false`
- Fixing booleans and `type: bool` where required

* Fix remaining (new) validation issues

lib/ansible/modules/cloud/cloudstack/cs_router.py

@@ -40,34 +40,23 @@ options:
   service_offering:
     description:
       - Name or id of the service offering of the router.
-    required: false
-    default: null
   domain:
     description:
       - Domain the router is related to.
-    required: false
-    default: null
   account:
     description:
       - Account the router is related to.
-    required: false
-    default: null
   project:
     description:
       - Name of the project the router is related to.
-    required: false
-    default: null
   zone:
     description:
       - Name of the zone the router is deployed in.
       - If not set, all zones are used.
-    required: false
-    default: null
     version_added: "2.4"
   state:
     description:
       - State of the router.
-    required: false
     default: 'present'
     choices: [ 'present', 'absent', 'started', 'stopped', 'restarted' ]
   poll_async: