Getting ready for Teatro.io stage server
Remove unused method
Merge pull request #5099 from xjunior/patch-1

Remove unused method
Reimbursements model & Manual intervention resolution for Returns

- New Reimbursement model which encapsulates the concept of reimbursing a set of accepted return items, which will be reimbursed via one or more reimbursement methods (e.g., refunds, exchanges, store credits, etc)
- Moved refund logic from customer return into Reimbursement
- Ability to resolve "manual_intervention_required" returns items in the Admin UI
- Provide preview of how reimbursements will be parceled out before performing them
- Add a default "ReimbursementPerformer" that figures out how to distribute a reimbursement

Other enhancements/fixes:

- Suggested amounts now update on input changes
- Add generic "success/notice/error" state colors
- New Admin show page for customer returns
- Remove customer return refund endpoint
- new Admin ReimbursementsController & ReturnItemsController

Created by @richardnuno & @jordan-brough

Fixes #5098
Fix broken spec.
Merge pull request #5067 from semenyukdmitriy/teatro_stage

Getting ready for Teatro.io stage server
Validate uniqueness of order numbers... Why was this FIXME never fixed until now... Fixes #5102