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/README.md

@@ -1,73 +0,0 @@
-## Local development
-
-#### 1. Start local server in a separate terminal.
-
-```
-# Typically run the local server with:
-cd server && make run
-
-# Or build and distribute webapp including channels and playbooks
-# so that their product URLs do not rely on Webpack dev server.
-# Especially important when running tests inside the Playwright's docker container.
-cd webapp && make dist
-cd server && make run-server
-```
-
-#### 2. Install dependencies and run the test.
-
-```
-# Install npm packages
-npm i
-
-# Install browser binaries as prompted if Playwright is just installed or updated
-# See https://playwright.dev/docs/browsers
-npx playwright install
-
-# Run a specific test of all projects -- Chrome, Firefox, iPhone and iPad.
-# See https://playwright.dev/docs/test-cli.
-npm run test -- login
-
-# Run a specific test of a project
-npm run test -- login --project=chrome
-
-# Or run all tests
-npm run test
-```
-
-#### 3. Inspect test results at `/test-results` folder when something fails unexpectedly.
-
-## Updating screenshots is done strictly via Playwright's docker container for consistency
-
-#### 1. Run docker container using latest focal version
-
-Change to the root directory, then run the docker container. (See https://playwright.dev/docs/docker for reference.)
-
-```
-docker run -it --rm -v "$(pwd):/mattermost/" --ipc=host mcr.microsoft.com/playwright:v1.49.1-noble /bin/bash
-```
-
-#### 2. Inside the docker container
-
-```
-export PW_BASE_URL=http://host.docker.internal:8065
-export PW_HEADLESS=true
-cd mattermost/e2e-tests/playwright
-
-# Install npm packages. Use "npm ci" to match the automated environment
-export PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 npm ci
-
-# Run specific test. See https://playwright.dev/docs/test-cli.
-npm run test -- login --project=chrome
-
-# Or run all tests
-npm run test
-
-# Update snapshots
-npm run test -- login --update-snapshots
-```
-
-## Page/Component Object Model
-
-See https://playwright.dev/docs/test-pom.
-
-Page and component abstractions are located at `./support/ui`. They should be established before writing a spec file so that any future changes in the DOM structure will be made in one place only. No static UI text or fixed locator should be written in the spec file.