Add ability to delete nodes in editor

src/app/service/editor.service.ts

@@ -120,6 +120,26 @@ export class EditorService {
         return dirties.some(Boolean) || needSaves.some(Boolean);
     }
 
+    async deleteNode(nodeId: string) {
+        if ( !this.currentPage ) {
+            throw new NoPageLoadedError();
+        }
+
+        const node = this.currentNodes.find(maybeNode => maybeNode.UUID === nodeId);
+        if ( !node ) {
+            throw new Error('Invalid node ID.');
+        }
+
+        const editor = this.nodeIdToEditorContract[nodeId];
+        if ( editor ) {
+            await editor.performDelete();
+            delete this.nodeIdToEditorContract[nodeId];
+        }
+
+        this.currentNodes = this.currentNodes.filter(x => x.UUID !== nodeId);
+        this.dirtyOverride = true;
+    }
+
     canEdit() {
         if ( !this.currentPage ) {
             throw new NoPageLoadedError();