Lexical: Imported core lexical libs

Imported at 0.17.1, Modified to work in-app.
Added & configured test dependancies.
Tests need to be altered to avoid using non-included deps including
react dependancies.

resources/js/wysiwyg/lexical/table/LexicalTableCommands.ts

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+
+import type {LexicalCommand} from 'lexical';
+
+import {createCommand} from 'lexical';
+
+export type InsertTableCommandPayloadHeaders =
+  | Readonly<{
+      rows: boolean;
+      columns: boolean;
+    }>
+  | boolean;
+
+export type InsertTableCommandPayload = Readonly<{
+  columns: string;
+  rows: string;
+  includeHeaders?: InsertTableCommandPayloadHeaders;
+}>;
+
+export const INSERT_TABLE_COMMAND: LexicalCommand<InsertTableCommandPayload> =
+  createCommand('INSERT_TABLE_COMMAND');