Accept source attributes in PaymentsController to fix backend payment processing.

Fixes #3823
[backend] Use the controller name rather than Object when a model does not exist for authorize_admin method

Fixes #3622
CreateAdjustment promotion action now associates adjustments through both order_id and adjustable_id.

Fixes #3858
[frontend] Removed scopes/dynamic.rb

The price_scopes_for method defined in this does not appear to be used anywhere
Fix issue where cancelling a line item delete didn't actually cancel it

Fixes #3862
Refactor ReturnAuthorization#generate_number

Fixes #3864