Update CSS optimization (using CDN for bootstrap) and mysql compat

tienda/static/scss/custom.scss

@@ -1,5 +1,4 @@
 @use 'sass:list';
-@import "bootstrap/bootstrap";
 $priceColor: #5abf5a;
 $primaryColor: (
     #FE8D90,

tienda/templates/tienda/base.html

@@ -7,6 +7,7 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Document</title>
+    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.8/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-sRIl4kxILFvY47J16cr9ZwB07vP4J8+LH7qKQnuqkuIAvNWLzeN8tE5YBujZqJLB" crossorigin="anonymous">
     <link rel="preload" href="{% static 'css/custom.css' %}" as="style" onload="this.onload=null;this.rel='stylesheet'">
     <noscript><link rel="stylesheet" href="{% static 'css/custom.css' %}"></noscript>
     <style>