ResourceLoader Module for serving json based localization messages

ApiULSLocalization is still present since we have to provide live
language preview feature.

Moved the loading of json file to includes/JsonMessageLoader.php

Also moved all RL modules to includes folder.

Bug: 56509
Change-Id: Ic39dec1c484982fb07edd167e83794c0b5f470ee

Resources.php

@@ -15,6 +15,10 @@ $wgResourceModules['ext.uls.languagenames'] = array(
 	'class' => 'ResourceLoaderULSModule'
 );
 
+$wgResourceModules['ext.uls.messages'] = array(
+	'class' => 'ResourceLoaderULSJsonMessageModule'
+);
+
 $wgResourceModules['ext.uls.buttons'] = array(
 	'styles' => 'resources/css/ext.uls.buttons.css',
 ) + $resourcePaths;
@@ -68,7 +72,7 @@ $wgResourceModules['ext.uls.init'] = array(
 		'jquery.json',
 		'jquery.cookie',
 		'jquery.uls',
-		'ext.uls.i18n',
+		'ext.uls.messages',
 	),
 	'position' => 'top',
 ) + $resourcePaths;