Add PreProd module to Identity for CODE

When the application is running in "prod-mode" but isn't actually in
production (e.g. CODE) we still need to create a PreProd injector.
Initial responsive forms for desktop
Merge branch 'master' of https://github.com/guardian/frontend into identity-responsive-forms
Merge branch 'master' of https://github.com/guardian/frontend into identity-responsive-forms
Merge remote-tracking branch 'origin/profile-user-details' into identity-responsive-forms
Merge branch 'master' of https://github.com/guardian/frontend into identity-responsive-forms
Changes to responsive forms
Minor css changes from Alastair
Remove IsFacia object
Add flexbox mixins
Remove FaciaSwitch from switches
Add guss layout component
Add linkslist pattern
Abstract vertical item separator
Set browser capability settings in IE css
Bump version up of news container
Import new responsive layout patterns
Remove v2 styles and import v3 styles
Import linkslist pattern
Special v3 fragment for the news container