Fixing support for remembering your cart after logging in as well as remembering your last order you were working on after logging out and then back in again.

Fixes #5075
Fixes #5273
Fixes spree/spree_auth_devise#220
add meta title to products

Closes #5276
Extracting Spree::ShippingMethod.find_by_name from create_shipments_from_params because it should be Spree::ShippingMethod.find_by_admin_name but this change needs to be handled carefully

Closes #5275
make 'Manage Variants' translatable

Closes #5277
provide status code on promotion handler

This change adds a status_code to the JSON response for the promotion code response object. It's a little bit brittle to bind on the translation message from ```Spree.t``` and sometimes more granularity is needed then success/error. The status_code should hopefully solve this.

Closes #5234
Spree::Zone#country_list fix

Just fixing wrong default value of case expression - should return an Array instance, ie. `[]` instead of `nil`.

Fixes #4827
Add missing translation.
Add state_text to StockLocation

I'm working on a revision to `Spree::TaxCloud`, and we use the `StockLocation` addresses pretty heavily. It'd be a huge help to have the `state_text` method that exists in the [`Spree::Address` model](https://github.com/spree/spree/blob/master/core/app/models/spree/address.rb#L39).

Fixes #4872
Removing unnecessary controllers and views from the admin
Fixes #5280