feat: Add user purchase and receipt management

- Implemented 'Mis Compras' and 'Mis Recibos' pages for users to view their orders and payment receipts.
- Enhanced address validation in 'editar_direccion.html' to ensure cities and postal codes belong to Almería.
- Added shipping address display in seller order details on 'pedidos_vendedor.html'.
- Updated user portal to include links to purchases and receipts.
- Introduced email verification functionality during user registration.
- Refactored email sending utility for better error handling and logging.
- Improved session management for checkout processes with selected shipping addresses.

tienda/admin.py

@@ -1,12 +1,12 @@
 from django.contrib import admin
-from .models import Category, Image, Product, Cart, CartItem, Order, OrderItem, OrderMessage
+from .models import Category, Image, Product, Cart, CartItem, Order, OrderItem, OrderMessage, User, VerificationCode
 # Register your models here.
 
 admin.site.register(Category)
 admin.site.register(Image)
 admin.site.register(Product)
-
-
+admin.site.register(User)
+admin.site.register(VerificationCode)
 class CartItemInline(admin.TabularInline):
     model = CartItem
     extra = 0