A stub for integration tests to be run locally; part of #8487
To run tests, you need to:
1. Build IDE package: `./run ide build`
2. set ENSO_TEST_USER and ENSO_TEST_USER_PASSWORD to some working credentials (I used my personal account, but there will be also test user soon)
3. run `corepack pnpm -r --filter enso exec playwright test`
The tests are run with a separate projects directory set up in tmpdir, so any local workspace dir is not affected.
The only test so far just checks if it's possible to log in and create a new project.
