Fix using check payment method in admin.
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
call reimbursement with id method
Add remibursement credits to admin panel under refunds

Closes #5283
promotions api show

Closes #5233
Use Rails environments instead of DB configurations

In the admin forms for Spree::PaymentMethod and Spree::Tracker the collection used for the environment field is the database configuration keys. This is wrong and it becomes quite apparent in the case of applications that connect to more than one database. This commit replaces said collection with a collection of the available environment configurations in '/config/environments/'.

Closes #5170
add specs for rails_environments helper method introduced in #5170
implement the code from #4488 by @k-akarsh.

Closes #5286