update fontawesome integration and add kit support

app/Admin/Integrations.php

@@ -7,6 +7,7 @@ class Integrations
     public function __construct()
     {
         add_action( 'wp_head',  [$this, 'FathomAnalytics']);
+        add_action( 'wp_footer',  [$this, 'FontAwesomeKit'], 100);
     }
 
     public function FathomAnalytics()
@@ -21,4 +22,17 @@ class Integrations
 
         <?php endif;
     }
+
+    public function FontAwesomeKit()
+    {
+        $kit = get_field('badegg_integrations_fontawesome_kit', 'option');
+
+        if($kit): ?>
+
+<!-- FontAwesome Kit -->
+<script src="https://kit.fontawesome.com/<?= $kit ?>.js" crossorigin="anonymous"></script>
+<!-- / FontAwesome Kit -->
+
+        <?php endif;
+    }
 }