client: Rename directory from assets to client

This will make it clearer that it is a somewhat standalone component.

Author: jtojnar

.gitignore

@@ -1,4 +1,4 @@
-/assets/.parcel-cache
+/client/.parcel-cache
 /data/favicons/*.png
 /data/favicons/*.jpg
 /data/thumbnails/*.png

.php-cs-fixer.php

@@ -1,7 +1,7 @@
 <?php
 
 $finder = PhpCsFixer\Finder::create()
-    ->exclude('assets')
+    ->exclude('client')
     ->exclude('utils')
     ->in(__DIR__)
     ->name('*.phtml');