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_instance_nic.py

@@ -47,45 +47,32 @@ options:
   ip_address:
     description:
       - IP address to be used for the nic.
-    required: false
-    default: null
   vpc:
     description:
       - Name of the VPC the C(vm) is related to.
-    required: false
-    default: null
   domain:
     description:
       - Domain the instance is related to.
-    required: false
-    default: null
   account:
     description:
       - Account the instance is related to.
-    required: false
-    default: null
   project:
     description:
       - Name of the project the instance is deployed in.
-    required: false
-    default: null
   zone:
     description:
       - Name of the zone in which the instance is deployed in.
       - If not set, default zone is used.
-    required: false
-    default: null
   state:
     description:
       - State of the nic.
-    required: false
     default: "present"
     choices: [ 'present', 'absent' ]
   poll_async:
     description:
       - Poll async jobs until job has finished.
-    required: false
-    default: true
+    type: bool
+    default: 'yes'
 extends_documentation_fragment: cloudstack
 '''