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
add an else statement for listing all promotion categories

load the new page on the index page via js

when no promotions, update add one promotion width

it says alpha twelve. There’s nothing that gets rendered to the right
as omega four, so this update fixes that aesteticly.

fixes #5563
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