allow for arbitrary grouping of property values and intro PropertyPage

lib/properties/PropertyGroup.ts

@@ -1,18 +1,16 @@
 import { PackagePropertyGroup } from "../types"
+import { PropertyPage } from "./PropertyPage"
 import { PropertyString } from "./PropertyString"
 
 export class PropertyGroup {
   private constructor(readonly data: PackagePropertyGroup) {}
   static of(options: {
-    description: string
-    value: (PropertyGroup | PropertyString)[]
-    name: string
+    header: string | null
+    values: (PropertyPage | PropertyString)[]
   }) {
     return new PropertyGroup({
-      type: "object",
-      name: options.name,
-      description: options.description,
-      value: options.value.map((x) => x.data),
+      header: options.header,
+      value: options.values.map((x) => x.data),
     })
   }
 }