FEAT: create isNPC geeter and add the prop on metada on actors

FEAT: create common method for documents sheets
FEAT: create BaseActorSheet and implementation

module/data/actor/base.mjs

@@ -3,13 +3,15 @@
  * @typedef {Object} ActorDataModelMetadata
  * @property {string} label - A localizable label used on application.
  * @property {string} type - The system type that this data model represents.
+ * @property {Boolean} isNPC - This data model represents a NPC?
  */
 export default class BaseDataActor extends foundry.abstract.TypeDataModel {
     /** @returns {ActorDataModelMetadata}*/
     static get metadata() {
         return {
             label: 'Base Actor',
-            type: 'base'
+            type: 'base',
+            isNPC: true,
         };
     }
 

module/data/actor/character.mjs

@@ -28,7 +28,8 @@ export default class DhCharacter extends BaseDataActor {
     static get metadata() {
         return foundry.utils.mergeObject(super.metadata, {
             label: 'TYPES.Actor.character',
-            type: 'character'
+            type: 'character',
+            isNPC: false,
         });
     }