Application prefs section (#2758)

* Add code for creating/managing apps to settings section

* Add specs for app changes

* Fix controller spec

* Fix view file I pasted over by mistake

* Add locale strings. Add 'my apps' to nav

* Add Client ID/Secret to App page. Add some visual separation

* Fix rubocop warnings

* Fix embarrassing typo

I lost an `end` statement while fixing a merge conflict.

* Add code for creating/managing apps to settings section

- Add specs for app changes
- Add locale strings. Add 'my apps' to nav
- Add Client ID/Secret to App page. Add some visual separation
- Fix some bugs/warnings

* Update to match code standards

* Trigger notification

* Add warning about not sharing API secrets

* Tweak spec a bit

* Cleanup fixture creation by using let!

* Remove unused key

* Add foreign key for application<->user

config/routes.rb

@@ -79,6 +79,11 @@ Rails.application.routes.draw do
     end
 
     resource :follower_domains, only: [:show, :update]
+
+    resources :applications do
+      put :regenerate
+    end
+
     resource :delete, only: [:show, :destroy]
 
     resources :sessions, only: [:destroy]