Update README and some TSDoc comments
- Add more information to the README about the packages and examples
- Update TSDoc comments
- Move options for the get method to its own interface for better TSDoc support
- Added stricter type to the get method, added a test
Do we want to add more examples to the TSDoc comments? Or to the README? Or as a page in https://www.drupal.org/docs/develop/decoupled-drupal/api-client ?
Closes #3391141