Large scale refactor to add class support!

Instance classes are now strongly typed with real property fields that
are derived from the JSON API Dump! This required a lot of reworking
across the board:

- Classes and Enums are auto-generated in the 'Generated' folder now.
This is done using a custom built-in plugin, which can be found in
the Plugins folder of this project.
- Property objects are now tied to .NET's reflection system. Reading
and writing from them will try to redirect into a field of the
Instance they are bound to.
- Property types that were loosely defined now have proper data types
(such as Color3uint8, Content, ProtectedString, SharedString, etc)
- Fixed an error with the CFrame directional vectors.
- The binary PRNT chunk now writes instances in child->parent order.
- Enums are now generated correctly, with up-to-date values.
- INST chunks are now referred to as 'Classes' instead of 'Types'.
- Unary operator added to Vector2 and Vector3.
- CollectionService tags can now be manipulated per-instance using
the Instance.Tags member.
- The Instance.Archivable property now works correctly.
- XML files now save/load metadata correctly.
- Cleaned up the property tokens directory.

I probably missed a few things, but that's a general overview of
everything that changed.

XmlFormat/Tokens/SharedString.cs

@@ -0,0 +1,25 @@
+using System.Xml;
+using RobloxFiles.DataTypes;
+
+namespace RobloxFiles.XmlFormat.PropertyTokens
+{
+    public class SharedStringToken : IXmlPropertyToken
+    {
+        public string Token => "SharedString";
+
+        public bool ReadProperty(Property prop, XmlNode token)
+        {
+            string md5 = token.InnerText;
+            prop.Type = PropertyType.SharedString;
+            prop.Value = new SharedString(md5);
+
+            return true;
+        }
+
+        public void WriteProperty(Property prop, XmlDocument doc, XmlNode node)
+        {
+            SharedString value = prop.CastValue<SharedString>();
+            node.InnerText = value.MD5_Key;
+        }
+    }
+}