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/Server/Attributes.cs

@@ -122,14 +122,14 @@ namespace Server
     [AttributeUsage(AttributeTargets.Property)]
     public class CommandPropertyAttribute : Attribute
     {
-        public CommandPropertyAttribute(AccessLevel level, bool readOnly)
+        public CommandPropertyAttribute(
+            AccessLevel level,
+            bool readOnly = false,
+            bool canModify = false
+        ) : this(level, level)
         {
-            ReadLevel = level;
             ReadOnly = readOnly;
-        }
-
-        public CommandPropertyAttribute(AccessLevel level) : this(level, level)
-        {
+            CanModify = canModify;
         }
 
         public CommandPropertyAttribute(AccessLevel readLevel, AccessLevel writeLevel)
@@ -139,9 +139,8 @@ namespace Server
         }
 
         public AccessLevel ReadLevel { get; }
-
         public AccessLevel WriteLevel { get; }
-
         public bool ReadOnly { get; }
+        public bool CanModify { get; }
     }
 }