Python code modernization, 3/n (#1157)

* Remove __metaclass__ = type.

for i in $(grep -REl '__metaclass__ = type' plugins/ tests/); do
  sed -e '/^__metaclass__ = type/d' -i $i;
done

* Remove super arguments, and stop inheriting from object.

plugins/module_utils/_api/api/client.py

@@ -115,7 +115,7 @@ class APIClient(_Session, DaemonApiMixin):
         use_ssh_client=False,
         max_pool_size=DEFAULT_MAX_POOL_SIZE,
     ):
-        super(APIClient, self).__init__()
+        super().__init__()
 
         fail_on_missing_imports()
 
@@ -493,7 +493,7 @@ class APIClient(_Session, DaemonApiMixin):
 
     def get_adapter(self, url):
         try:
-            return super(APIClient, self).get_adapter(url)
+            return super().get_adapter(url)
         except _InvalidSchema as e:
             if self._custom_adapter:
                 return self._custom_adapter

plugins/module_utils/_api/api/daemon.py

@@ -17,7 +17,7 @@ from .. import auth
 from ..utils.decorators import minimum_version
 
 
-class DaemonApiMixin(object):
+class DaemonApiMixin:
     @minimum_version("1.25")
     def df(self):
         """