feat(dkim): make key size configurable and allow keys to be rotated

config/routes.rb

@@ -12,12 +12,16 @@ Rails.application.routes.draw do
       match :verify, on: :member, via: [:get, :post]
       get :setup, on: :member
       post :check, on: :member
+      post :regenerate_dkim, on: :member
+      post :cancel_dkim_regeneration, on: :member
     end
     resources :servers, except: [:index] do
       resources :domains, only: [:index, :new, :create, :destroy] do
         match :verify, on: :member, via: [:get, :post]
         get :setup, on: :member
         post :check, on: :member
+        post :regenerate_dkim, on: :member
+        post :cancel_dkim_regeneration, on: :member
       end
       resources :track_domains do
         post :toggle_ssl, on: :member