Refactor namespaces and simplify DTOs

Updated namespaces to align with the new DigitalData.Core structure, replacing `DigitalData.Core.Abstractions` with `DigitalData.Core.Application.Interfaces` and `DigitalData.Core.Client.Interface`. Removed the `IUnique<int>` interface from several DTOs, simplifying their design and altering the handling of entity identification. Updated project files to reflect new dependency versions for improved compatibility and features. Cleaned up using directives to remove obsolete references, enhancing code maintainability.

EnvelopeGenerator.Domain/Entities/Config.cs

@@ -1,6 +1,5 @@
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
-using System.Text.Json.Serialization;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
@@ -22,10 +21,5 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Column("EXPORT_PATH", TypeName = "nvarchar(256)")]
         public string ExportPath { get; set; }
-
-        [Obsolete("Configuration does not have an ID; it represents a single table in the database.")]
-        [NotMapped]
-        [JsonIgnore]
-        public int Id => throw new InvalidOperationException("This configuration does not support an ID as it represents a single table in the database.");
     }
 }

EnvelopeGenerator.Domain/Entities/EnvelopeReceiverBase.cs

@@ -46,7 +46,7 @@ namespace EnvelopeGenerator.Domain.Entities
         public string PhoneNumber { get; set; }
         
         [NotMapped]
-        public (int Envelope, int Receiver) Id => (Envelope: EnvelopeId, Receiver: ReceiverId);
+        public Tuple<int, int> Id => Tuple.Create(EnvelopeId, ReceiverId);
 
         [NotMapped]
         public bool HasPhoneNumber => !string.IsNullOrWhiteSpace(PhoneNumber);