Add typed procedure descriptors and Exec invoker

DynamORM.Tests/Helpers/ProcedureParameterModels.cs

@@ -139,4 +139,18 @@ namespace DynamORM.Tests.Helpers
         [ProcedureParameter("status", Direction = ParameterDirection.Output, Order = 1, DbType = DbType.Int32)]
         public int Status { get; set; }
     }
+
+    [Procedure(Name = "sp_exec_test", Owner = "dbo")]
+    public class ExecProcedureDescriptor : Procedure<ProcedureParameterObject>
+    {
+    }
+
+    public class ExecProcedureDefaultDescriptor : Procedure<ProcedureParameterObject>
+    {
+    }
+
+    [Procedure(Name = "sp_exec_result")]
+    public class ExecProcedureDescriptorWithExplicitResult : Procedure<ProcedureParameterColumnFallbackObject, ProcedureAttributedResult>
+    {
+    }
 }