Factory generator

[tomasvanrijsse]

I made a factory generator so tests are easier to setup for users of my SDK.

### Testing

When testing code that uses the SDK, you can mock the connector and its responses using factories. The SDK includes factory classes for all DTOs that make it easy to generate test data.

Here's an example of testing the `CustomerController` from the example above:

```php
test('it displays customers', function () {
    // Generate test data using factories
    $customer = CustomerDto::factory()->state([
        'number' => 'CUST001',
        'name' => 'Acme Corporation',
        'status' => 'Active',
    ])->make();

    // Create mock responses using factory-generated data
    $mockClient = MockClient::global([
        CustomerGetAllRequest::class => MockResponse::make([
            'data' => [$customer->toArray()],
        ], 200)
    ]);

    // Make request
    $response = $this->get(route('customers.index'));

    // Assert
    $response->assertOk();
    $response->assertViewHas('customers');
    $response->assertViewHas('defaultCustomer');
});