v3.6.5 Ravishing Radishes

Congrats @gucci-ninja on your first contribution to the OFN code base!

A smattering of bug fixes, one big performance improvement, and a whole bunch of cleanup to keep everything in good working order and prepare for another Rails upgrade.

User facing changes 👀

#7363 Release customer balances to all users
#7312, #7389, #7317 Updated translations
#7207 Fixed a bug where some subscriptions that failed to create orders would not appear in the summary email.
#7299 Changing the quantity of line items for an order in the backoffice now automatically updates the appropriate fees.
#7338 Removes arrows showing up on number input on Chrome/Safari/Edge
#7334 Fixed outstanding balance sum in payment report
#7300 Fixed a bug in the admin edit order screen where on-demand variants could not have their quantity increased.
#7313 Add non-breaking space to avoid unwanted line breaks on unit price
#7349 Fixed a bug where item variants with unit scales would cause the shopfront to not load.
#7287 It's not possible to change the contents of cancelled orders any more to avoid inconsistencies.
#6924 Added Tax Categories to Shipping Methods.
#7265 Fixed a bug where a canceled order could have its adjustments edited.
#7309 Update README.md

Technical changes 🔧

#7288 Simpler setup of code quality checks.
#7330 Added soft-deletion to ReturnAuthorization and improved unscoping on adjustment originators.
#7340 Added test coverage on updating orders with deleted enterprise fees.
#7328 Removed included_tax scope from Adjustment
#7316 Removed unused code: Order#ensure_updated_shipments
#7351 Removed unused code: TagRule::DiscountOrder
#7352 Removed unused Spree::Api::ApiHelpers
#7314 Renamed #charge_shipping_and_payment_fees! to #set_payment_amount!
#7355 Updated rspec syntax for Rails 5.2
#7342 Delete unused code
#7321 Removed old references to Bugherd
#7350 Makes features toggled by default only for development environments.
#7356 Fixed a failing shipments controller spec
#7325 Upgraded wkhtmltopdf-binary gem
#7311 Excluded sample data tasks from codecov reporting.
#7343 Remove dead code
#7344 Adapt code to rails 5.2
#7236 Improved touch logic on Exchanges
#7319 Bump rubocop from 1.12.0 to 1.12.1
#7213 Make bullet activation optional
#7260 Add automated tests for unit price in backoffice
#7294 Updated interface in OrderBalance to handle additional methods.
#7174 Remove Spree ResourceController callbacks