Add init script to make onboarding easier

[AlexSkrypnyk]

We need to simplify the setup process as per https://github.com/AlexSkrypnyk/drupal_extension_scaffold?tab=readme-ov-file#setup

• Look at the init script from another scaffold and implement the same approach (copy/paste)
  https://github.com/AlexSkrypnyk/scaffold/blob/main/init.sh
• Add bats tests into .scaffold/tests/bats dir (same as in https://github.com/AlexSkrypnyk/scaffold) repo
• Make sure that the script removes .scaffold dir after run.

The questions themselves should be adjusted for this repo:

1. namespace
2. name
3. machine_name
4. type: module or theme
5. ci_provider - GitHub Actions or CircleCI