Add newsletter subscriber as an interactor.
Add newsletter subscriptions controller and route.
Use rails helpers to render localised newsletter subscription form.
Style newsletter subscription form.
Add border separator

I will match the height of this once we alter the content in the other
columns within this row
Add authenticity token to newsletter sign up form.
Define connection post method to handle HTTP 422 status response.
Display localised success and error messages on signup subscription.
Require ruby files not everything.
Add newsletter signup feature, steps and page object.