Fix admin order open/close adjustments to affect all adjustments

* The previous code was just opening and closing the order-specific
  adjustments, not the line items or shipping adjustments.

Conflicts:
	backend/spec/controllers/spree/admin/orders_controller_spec.rb

fixes #5558
Fix gitignore to exclude vendor

* Build scripts install to ./vendor, after testing something locally via
  the officially supported method `git status` should still list a
  pristine repository.

fixes #5573