Refactor participatory budgets in draft mode

Previously the draft mode was a phase of the PB, but that had some
limitations.

Now the phase drafting disappears and therefore the PB can have the
status published or not published (in draft mode).

That will give more flexibility in order to navigate through the
different phases and see how it looks for administrators before
publishing the PB and everybody can see.

By default, the PB is always created in draft mode, so it gives you
the flexibility to adjust and modify anything before publishing it.

config/routes/admin.rb

@@ -53,6 +53,7 @@ namespace :admin do
 
   resources :budgets do
     member do
+      patch :publish
       put :calculate_winners
     end