Remove jquery.i18n code that the ULS extension overrides

Instead of using the whole jquery.i18n code, use only required parts
that are not customized in MW ULS. For this define a new RL module
ext.uls.i18n.

Also refactor MW message store for jquery.i18n.

Change-Id: Idda9fe505428ade409d937314d7216ebb4232c36

lib/jquery.i18n/languages/ga.js

@@ -0,0 +1,38 @@
+/**
+ * Irish (Gaeilge) language functions
+ */
+( function ( $ ) {
+	'use strict';
+
+	$.i18n.languages.ga = $.extend( {}, $.i18n.languages['default'], {
+		convertGrammar: function ( word, form ) {
+			if ( form === 'ainmlae' ) {
+				switch ( word ) {
+				case 'an Domhnach':
+					word = 'Dé Domhnaigh';
+					break;
+				case 'an Luan':
+					word = 'Dé Luain';
+					break;
+				case 'an Mháirt':
+					word = 'Dé Mháirt';
+					break;
+				case 'an Chéadaoin':
+					word = 'Dé Chéadaoin';
+					break;
+				case 'an Déardaoin':
+					word = 'Déardaoin';
+					break;
+				case 'an Aoine':
+					word = 'Dé hAoine';
+					break;
+				case 'an Satharn':
+					word = 'Dé Sathairn';
+					break;
+				}
+			}
+
+			return word;
+		}
+	} );
+}( jQuery ) );