frontend implementation of Domains.duplicate()

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

lng/de.lng.php

@@ -489,6 +489,8 @@ return [
 		'adminguide' => 'Admin Guide',
 		'userguide' => 'User Guide',
 		'apiguide' => 'API Guide',
+		'domain_duplicate' => 'Domain duplizieren',
+		'domain_duplicate_named' => '%s duplizieren',
 	],
 	'apikeys' => [
 		'no_api_keys' => 'Keine API Keys gefunden',

lng/en.lng.php

@@ -500,6 +500,8 @@ return [
 		'adminguide' => 'Admin guide',
 		'userguide' => 'User guide',
 		'apiguide' => 'API guide',
+		'domain_duplicate' => 'Duplicate domain',
+		'domain_duplicate_named' => 'Duplicate %s',
 	],
 	'apcuinfo' => [
 		'clearcache' => 'Clear APCu cache',