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/.gitignore

@@ -0,0 +1,16 @@
+# playwright tests
+test/logs
+test/node_modules
+test/playwright-report
+test/test-results
+test/results
+test/storage_state
+test/specs-results
+test/specs/**/*-darwin.png
+test/specs/**/*-window.png
+test/specs/accessibility/**/*-snapshots
+test/.eslintcache
+
+# build
+dist
+*.tsbuildinfo