Add icon to remove stock items from product section
Use new stock location api in product stock management

[Fixes #3051]

Conflicts:
	backend/app/controllers/spree/admin/stock_items_controller.rb
	backend/config/routes.rb
	backend/spec/requests/admin/products/stock_management_spec.rb

Conflicts:
	backend/app/controllers/spree/admin/stock_items_controller.rb
	backend/config/routes.rb
	backend/spec/requests/admin/products/stock_management_spec.rb