Add Transaction Merchant management (#686)

* Add basid crud for merchant management

* Tweak UI and add localization

* Fix lint

* Add filtering by merchant

* Add tests

* Add stimulus controller to update avatar in merchant form

* Add line between merchant rows

* Change default merchant color

* Cleanup

config/routes.rb

@@ -25,7 +25,7 @@ Rails.application.routes.draw do
     # TODO: These are *placeholders*
     # Uncomment `only` and add the necessary actions as they are implemented.
     resources :rules, only: [ :index ]
-    resources :merchants, only: [ :index ]
+    resources :merchants, only: %i[index new create edit update destroy]
   end
 
   resources :transactions do