Add Spree::Admin::RootController for redirecting purposes.

Currently, is really difficult to redirect to a different tab when the
user has logged in if said users cannot at least :admin, :index
`Spree::Order`s.

This commit adds a controller that handles `/admin` route so anyone can
easily redirect to another page (or implement any other logic).
User store location when signing in
Fixes #5418
Fixes #5125

Conflicts:
	core/lib/spree/core/controller_helpers/auth.rb
Fix specs broken by 09ccf8a
Fix specs broken by 87b3fa6
Include all adjustments in final shipment price

(Not solely promotions and taxes.) As per discussion in https://github.com/spree/spree/issues/5415

Fixes #5415
Fixes #5419
Fix broken specs from 4441fb42acfbf7ebf02a44c116f0d09d61c3b54f & c3a741c
refactor shipping calculator compute methods

clearer naming for methods

Fixes #5414
fix spec path in readme
Fixes #5423
refactoing code to call find_adjustment in before_action rather than calling it in each menthod
Fixes #5426
Add spec to ensure adjustment callback is fired.
Add comment explaining its important to use destroy_all.
Fix db:bootstrap task
Fixes #5431
Fixes #5432
Replace scoped with where(nil) as scoped was removed from Rails. See: http://stackoverflow.com/a/18199294 Fixes #5366
Add considered_safe to variable states

add translation for considered risky in order index

Add considered risky flag to orders index

Fixes #5374
Fix spec broken by 3eeb71d and add a regression check for it.
Add Canadian provinces. Fixes #5016
fixed style quotes to path gem spree_core
fixes #5435
Remove some bad factory values

These numbers are autogenerated by the models so we don't need to set them in the factories.
On top of that, the numbers were being set 1) without their normal prefixes, 2) to the exact same value for every instance of the factory, 3) to the exact same values in two different factories.  These things caused errors in our app specs due to cross-model collisions that were a bit of a pain to track down.

Fixes #5437
Allow order admin to filter on risky
Fixes #5438
Add self dependencies.

Fixes #5157
Fixes #5328