ipauser: Enable batch command use with keeponly

The use of the batch command is enabled for execute_ipa_commands.

Additionally keeponly is set to ["randompassword"] as this is the only
parameter that is used from the data returned from the commands.

plugins/modules/ipauser.py

@@ -1796,7 +1796,7 @@ def main():
         # Execute commands
 
         changed = ansible_module.execute_ipa_commands(
-            commands, result_handler,
+            commands, result_handler, batch=True, keeponly=["randompassword"],
             exit_args=exit_args, single_user=users is None)
 
     # Done