Remove unused routes related to documents

These routes aren't used since commits (2993ef8707, 88a7a29d27)
In parallel while these routes were being removed, the route file
was being split into different files, and they were included again
in the commit 1cd47da9d4.

config/routes/document.rb

@@ -1,7 +1 @@
-resources :documents, only: [:new, :create, :destroy] do
-  collection do
-    get :new_nested
-    delete :destroy_upload
-    post :upload
-  end
-end
+resources :documents, only: [:destroy]