… simplicity

Updated various properties in FedExShipmentProvider and related classes for better flexibility and simplicity. Made `FreightOnValue` nullable and changed `EncodedLabel` type to byte[]. Added new enum member to `ShippingDocumentType`. Set `ServiceType` and `PackagingType` dynamically. Added `Dimensions`, `LabelPrintingOrientation`, `LabelRotation`, and `CustomerImageUsages` properties. Simplified `RequestedDocumentTypes` and `Bytes` properties. Changed `PaymentType` from `RECIPIENT` to `SENDER`. Updated `FedExShipmentProviderTests` to save labels as PNG and modified the `international` address.

Added `System.Reflection.Emit` namespace to `FedExShipmentProvider.cs` for metadata and MSIL emission. Introduced `EmailNotificationDetail` object to `FedExShipmentProvider` class for detailed email notifications. Updated `PaymentType` to be dynamic based on `shipmentDetails.PaymentType.Name`. Implemented `CancelShipmentAsync` method in `FedExShipmentProvider` class to handle shipment cancellations and log exceptions. Uncommented test lines in `FedExShipmentProviderTests` to include shipment cancellation tests.

This commit enhances the functionality of the FedEx rate provider and related tests. Changes include setting the `AccountNumber` directly in `FedexRateProvider.cs`, adding `StateOrProvinceCode` and `City` properties for `Shipper` and `Recipient` addresses, and setting `PackageSpecialServices` based on the `SignatureRequiredOnDelivery` flag. A condition is added to check for non-US `DestinationAddress` and set `CustomsClearanceDetail` accordingly. In `FedExShipmentProvider.cs`, the `CommercialInvoice` property is now set with `SpecialInstructions`. Lastly, the output line in `FedExRateProviderTests.cs` now includes the full name of the `rateService` type.