test: bare-bones e2e testing with playwright (#416)

.github/actions/setup/action.yml

.github/workflows/e2e-test.yml

package.json

packages/desktop-client/.gitignore

packages/desktop-client/README.md

packages/desktop-client/e2e/page-models/account-page.js

...ages/desktop-client/e2e/page-models/configuration-page.js

packages/desktop-client/e2e/page-models/navigation.js

packages/desktop-client/e2e/transactions.test.js

packages/desktop-client/package.json

packages/desktop-client/playwright.config.js

packages/loot-design/src/components/common.js

packages/loot-design/src/components/sidebar.js

yarn.lock