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/source_control/gitlab_group.py

@@ -30,25 +30,18 @@ options:
     validate_certs:
         description:
             - When using https if SSL certificate needs to be verified.
-        required: false
         default: true
         aliases:
             - verify_ssl
     login_user:
         description:
             - Gitlab user name.
-        required: false
-        default: null
     login_password:
         description:
             - Gitlab password for login_user
-        required: false
-        default: null
     login_token:
         description:
             - Gitlab token for logging in.
-        required: false
-        default: null
     name:
         description:
             - Name of the group you want to create.
@@ -57,13 +50,10 @@ options:
         description:
             - The path of the group you want to create, this will be server_url/group_path
             - If not supplied, the group_name will be used.
-        required: false
-        default: null
     state:
         description:
             - create or delete group.
             - Possible values are present and absent.
-        required: false
         default: "present"
         choices: ["present", "absent"]
 '''