fix(core): Fixes some properties that cannot be modified ingame (#604)

- [X] Adds a property to `CommandProperty` to allow modifying `PropertyObject` where there is no property setter that is accessible.
- [X] Updates AosAttributes and friends

Example of how to make this work:
```cs
        [CommandProperty(AccessLevel.GameMaster, canModify: true)]
        public AosWeaponAttributes WeaponAttributes { get; private set; }
```

This fix is necessary because in release mode the optimizer will sometimes _entirely remove the setter_ because it knows it can do something that is more efficient _when the property setter is private_. RunUO got around this by declaring a public setter explicitly that _was empty_.

### Screenshot
<img width="313" alt="Screen Shot 2021-05-15 at 11 34 01 PM" src="https://user-images.githubusercontent.com/3953314/118387955-49293c00-b5d6-11eb-8f31-a3b5e31bd18b.png">

Projects/UOContent/Items/Quivers/BaseQuiver.cs

@@ -38,7 +38,7 @@ namespace Server.Items
         public override int DefaultMaxWeight => 50;
         public override double DefaultWeight => 2.0;
 
-        [CommandProperty(AccessLevel.GameMaster)]
+        [CommandProperty(AccessLevel.GameMaster, canModify: true)]
         public AosAttributes Attributes { get; private set; }
 
         [CommandProperty(AccessLevel.GameMaster)]