MM-62954 E2E/Playwright shared library (#30177)

* feat: Add package.json for Playwright library with dependencies

* feat: Add explicit exports for test.config in playwright-lib package

* feat: Add initialization setup for Mattermost E2E testing with admin and user client

* fix: Update package dependencies and resolve TypeScript build errors

* feat: Update package exports for test.config to support both CommonJS and ESM

* playwright shared library

* add README, fix pipeline

* keep file structures, move report up to playwright

* minimize API, use the prerelease versions of client and types

* bump version

* update package*.json

* resolve merge conflict

* update depedencies and merge conflicts

* update readme and fix ci

* remove unnecessary export and list all external packages

* fix import for Client4

e2e-tests/playwright/report.webhookgen.js

@@ -1,6 +1,10 @@
-#!/usr/bin/env node
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+/* eslint-disable @typescript-eslint/no-require-imports */
 
 const fs = require('fs');
+
 const dayjs = require('dayjs');
 const duration = require('dayjs/plugin/duration');
 dayjs.extend(duration);
@@ -90,5 +94,5 @@ function generateWebhookBody() {
     };
 }
 
-let webhookBody = generateWebhookBody();
+const webhookBody = generateWebhookBody();
 process.stdout.write(JSON.stringify(webhookBody));