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/webfaction/webfaction_mailbox.py

@@ -39,12 +39,10 @@ options:
         description:
             - The password for the mailbox
         required: true
-        default: null
 
     state:
         description:
             - Whether the mailbox should exist
-        required: false
         choices: ['present', 'absent']
         default: "present"