added Class-Based Conditions

[Safemood]

Description

This pull request introduces a new feature to Discountify - Class-Based Conditions. This enhancement empowers users to define more sophisticated discount strategies by encapsulating custom logic within dedicated classes.

Changes Made

• Feature: Added support for Class-Based Conditions in the discount application process.
• Implementation: Introduced a flexible mechanism for users to create their own discount strategies by defining classes.
• Auto-Discovery: Classes placed under the App\Conditions namespace or within the app/conditions directory will be automatically discovered and available for use.

Usage Example

use App\Conditions\ConditionInterface;

class MoreThan1ProductsCondition implements ConditionInterface
{
    public string $slug = 'more_than_1_products_10';

    public int $discount = 10;

    public function __invoke(array $items): bool
    {
        return count($items) > 1;
    }
}