jquery.tablesorter: Move files to their own directory

* Reduce clutter in src/jquery/.
* Make it easier to see which files belong to which module, especially
  src/jquery/images/ which was confusingly shared between multiple modules.
  This also helps emphasize that while jquery.tablesorter.less is included,
  jquery.tablesorter.styles.less is not.

Also follows-up 8cdfcc5fd, which placed its style-module definition among
the 'mediawiki.*' modules instead of near the 'jquery.*' modules.

Change-Id: Ib639de5df323a36982ecdd89158a939beaaa2dd3

resources/Resources.php

@@ -112,13 +112,6 @@ return [
 			'resources/src/mediawiki.skinning/interface.css' => [ 'media' => 'screen' ],
 		],
 	],
-
-	'jquery.tablesorter.styles' => [
-		'targets' => [ 'desktop', 'mobile' ],
-		'styles' => [
-			'resources/src/jquery/jquery.tablesorter.styles.less',
-		],
-	],
 	'jquery.makeCollapsible.styles' => [
 		'targets' => [ 'desktop', 'mobile' ],
 		'class' => ResourceLoaderLessVarFileModule::class,
@@ -328,8 +321,8 @@ return [
 		'scripts' => 'resources/src/jquery/jquery.tabIndex.js',
 	],
 	'jquery.tablesorter' => [
-		'scripts' => 'resources/src/jquery/jquery.tablesorter.js',
-		'styles' => 'resources/src/jquery/jquery.tablesorter.less',
+		'scripts' => 'resources/src/jquery.tablesorter/jquery.tablesorter.js',
+		'styles' => 'resources/src/jquery.tablesorter/jquery.tablesorter.less',
 		'messages' => [ 'sort-descending', 'sort-ascending' ],
 		'dependencies' => [
 			'jquery.tablesorter.styles',
@@ -337,6 +330,12 @@ return [
 			'mediawiki.language.months',
 		],
 	],
+	'jquery.tablesorter.styles' => [
+		'targets' => [ 'desktop', 'mobile' ],
+		'styles' => [
+			'resources/src/jquery/jquery.tablesorter.styles.less',
+		],
+	],
 	'jquery.textSelection' => [
 		'scripts' => 'resources/src/jquery/jquery.textSelection.js',
 		'dependencies' => 'jquery.client',