Add init-drupal-profile target

Coming from #130 (closed), it would be nice to go beyond the basic Drupal-level setup, we may want to add a new target (followup ticket) to capture the post-initialization Drupal setup we do, ie. create a custom install profile, set up Config Enforce, etc.

See the early history of this project https://gitlab.com/consensus.enterprises/clients/l4e/-/commits/main?ref_type=HEADS for an example where we've done most of that by hand.