Fix module loading on MediaWiki 1.31 and earlier

368fe37a1a is broken when used on MediaWiki 1.31 and earlier because
it tries to add

  $modules['ext.uls.displaysettings']['dependencies'][]

although $modules['ext.uls.displaysettings'] does not exist.

The whole module definition must moved from extension.json to
UniversalLanguageSelector.hooks.php.

Change-Id: Ie8f7f084c965e6dee33fef03448004d5d8805f2c

extension.json

@@ -116,21 +116,6 @@
 			"localBasePath": "resources",
 			"remoteExtPath": "UniversalLanguageSelector/resources"
 		},
-		"ext.uls.displaysettings": {
-			"scripts": "js/ext.uls.displaysettings.js",
-			"styles": "css/ext.uls.displaysettings.less",
-			"dependencies": [
-				"ext.uls.languagesettings",
-				"ext.uls.mediawiki",
-				"ext.uls.webfonts",
-				"mediawiki.api",
-				"mediawiki.ui.checkbox",
-				"mediawiki.ui.button",
-				"mediawiki.user"
-			],
-			"localBasePath": "resources",
-			"remoteExtPath": "UniversalLanguageSelector/resources"
-		},
 		"ext.uls.geoclient": {
 			"scripts": "js/ext.uls.geoclient.js",
 			"dependencies": [
@@ -233,15 +218,6 @@
 			"localBasePath": "resources",
 			"remoteExtPath": "UniversalLanguageSelector/resources"
 		},
-		"ext.uls.preferences": {
-			"scripts": "js/ext.uls.preferences.js",
-			"dependencies": [
-				"mediawiki.user",
-				"mediawiki.api"
-			],
-			"localBasePath": "resources",
-			"remoteExtPath": "UniversalLanguageSelector/resources"
-		},
 		"ext.uls.webfonts": {
 			"scripts": "js/ext.uls.webfonts.js",
 			"dependencies": [