Restore enableWebfonts pref and remove uls-enable

This patch restores the enableWebfonts preference, stored inside
the uls-preferences blob. It existed as 'enable-webfonts' in
the past and was removed in
If735a733717596fae03042c5e277bd538bd8501f

Each wiki can be configured to load the fonts by default
using the new global variable $wgULSWebfontsEnabled.
Its default value is true (to load fonts).

This also removes the preference 'uls-enable', recently added in
I71b70d8ee7c3cad7f49b32e5dc494ef4fc1bdb2f

The initialization of ext.uls.webfonts.js is changed as well,
so that minimal webfonts JS library code is loaded,
and the rest is loaded only if a user requests it.

Bug: 60304
Change-Id: I49e812eae32266f165591c75fd67b86ca06b13f0

resources/js/ext.uls.inputsettings.js

@@ -75,7 +75,9 @@
 		 * Render the module into a given target
 		 */
 		render: function () {
-			var $enabledOnly;
+			var $enabledOnly,
+				webfonts = $( 'body' ).data( 'webfonts' );
+
 			this.dirty = false;
 			this.$parent.$settingsPanel.empty();
 			this.$imes = $( 'body' ).data( 'ime' );
@@ -91,7 +93,11 @@
 			this.prepareLanguages();
 			this.prepareToggleButton();
 			this.$parent.i18n();
-			$( 'body' ).data( 'webfonts' ).refresh();
+
+			if ( webfonts ) {
+				webfonts.refresh();
+			}
+
 			this.listen();
 		},