Remove private setters to make class immutable

Remove private setters to make Enumeration immutable. Otherwise, it's possible to change the property values. 

 ```csharp
 public override string ToString()
        {
            Name = "Whatever";
            return Name;
        }
```

## Summary

Remove private setters for public properties

src/Services/Ordering/Ordering.Domain/SeedWork/Enumeration.cs

@@ -7,9 +7,9 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Domain.SeedWork
 {
     public abstract class Enumeration : IComparable
     {
-        public string Name { get; private set; }
+        public string Name { get; }
 
-        public int Id { get; private set; }
+        public int Id { get; }
 
         protected Enumeration()
         {