Add Config File to Playwright Installation

Currently, we set the env variable PLAYWRIGHT_baseUrl in the docker compose file. This works, but we have to set the baseURL in the config file as well. Otherwise, we cannot use the goto command relatively. We always must use

// Without baseURL
await page.goto(process.env.PLAYWRIGHT_baseUrl + '/login');

// With baseURL configured
await page.goto('/login');

See doc: https://playwright.dev/docs/test-configuration