feat: reimplement server icon customization feature

- Add user_set_icon and user_set_icon_color to Server model fillable
- Add icon modal properties and methods to Overview component
- Add clickable icon button next to server hostname in layout
- Add icon picker modal with search, color selection, and preview
- Support for 100+ Remix icons across various categories
- Icons persist to database and display on page load

extensions/Servers/Proxmox/Models/Server.php

@@ -20,6 +20,8 @@ class Server extends Model
         'status',
         'hostname',
         'password',
+        'user_set_icon',
+        'user_set_icon_color',
     ];
 
     public function node()