Let rails handle RecordNotFound in orders controller

Fixes #4044
Avoid invalid query "SELECT DISTINCT DISTINCT" in order search

Weird issue. The double DISTINCT seems to be added by kaminari, couldn't
reproduce it in a spec or in clean rails app

e.g. This query would also result in the same error (or any query
similar within Spree)

    Shipment.where(inventory_units: { id: "a" }).includes(:inventory_units).uniq.page(1).to_a
Validate presence of name in CreditCard
Fix CreditCard sample data
Adding support for spree_xhr_post, spree_xhr_put, spree_xhr_delete

Fixes #4071
use the new line_item_description_text(line_item.description) method.

Removes all the deprecation warnings.
Fixes #4066
Backend taxon controller now using Spree::PermittedAttributes

Fixes #4069
Drop deprecated 'find_by' api to fetch user api key
Remove lib from autoload_paths

We don't want everything inside lib to be autoloaded, factories and test
helpers for example. Applications and extensions should manually require
what they need within lib (as it's already done most of the times
hopefully)
Fix bug when spinner is created every time progressbar is displayed
[Fixes #4065]
[backend] nil check for shipping_method in orders/_shipment

fixes #4025

Conflicts:
	backend/app/views/spree/admin/orders/_shipment.html.erb
Show destroy flash messages in admin backend

Fixes #4032
Really always include the confirm step preference

Fixes #3945
Add name_on_card translation

The frontend checkout spec was complaining about this
Add customer_id to gateway options

:customer and :email are both the email, it could be useful to uniquely
identifiy a customer on the gateway

Fixes #4051
Permit name to be passed through in source_attributes
Don't show confirmation step if payments are empty
[frontend] Set flash.now for gateway errors in CheckoutController

Fixes #4034
[frontend] Use flash.now for coupon application error in OrdersController

Otherwise this will carry over to the next request, which is not fun.

Fixes #4034
Fix 'Loading images' message for sample data not showing any product names