Attempt to auto-accept return items when received.

cherry-picked from 1319b82f8eee3cf516b25156542e32bba99a364d in spree master
Fix broken specs.

cherry-picked from 9d8d435baeca87577669e9fab258625ab0acb2ed in spree master
Specs for ReimbursementPerformer

- Add specs for ReimbursementPerformer

cherry-picked from 63c7fbea993b9c3d0620cbcf9cf031ee66cd4615 in spree master
Reimbursement Admin UI updates

- Don't show edit button for reimbursement if reimbursement has been finalized
- Add an admin reimbursements show page

cherry-picked from 896c2a59628c571962fad06cc09320be3033d756 in spree master
Fix rounding issue

Add some rounding in reimbursements to handle edge cases where multiple consecutive partial refunds
on the same order might result in rounding errors where we'd reimburse more than was originally
billed.

cherry-picked from 72356172c1209bce43ac07172953cc5aae0de803 in spree master
Add missing translation

Specs were complaining like this: https://gist.github.com/jordan-brough/336daa1b1648dd8609e8

cherry-picked from 43ad349c280fee3f209e6d10eb1a798f484b906b in spree master