added equipped and owner to item sheet

Additions:
- added equipped checkbox to item sheet
- added item owner to item properties list
- added some translations
- added some TODOs

Changes:
- item properties owner, equipped, quantity, storageLocation
  are only shown if item is owned by an actor
- moved item properties price and availability
  to details tab
- shortened ItemEquipped translation
- added item.actor and item.isOwned property values
  to data returned from DS4ItemSheet.getData
  (properties aren't accessible in Handlebars)

src/module/item/item-sheet.ts

@@ -26,7 +26,7 @@ export class DS4ItemSheet extends ItemSheet<DS4ItemDataType, DS4Item> {
 
     /** @override */
     getData(): ItemSheetData<DS4ItemDataType, DS4Item> {
-        const data = { ...super.getData(), config: CONFIG.DS4 };
+        const data = { ...super.getData(), config: CONFIG.DS4, isOwned: this.item.isOwned, actor: this.item.actor };
         console.log(data);
         return data;
     }