Remove tracker role

The current tracking section had a few issues:

* When browsing as an admin, this section becomes useless since no
investments are shown
* Browsing investments in the admin section, you're suddenly redirected
to the tracking section, making navigation confusing
* One test related to the officing dashboard failed due to these changes
and had been commented
* Several views and controller methods were copied from other sections,
leading to duplication and making the code harder to maintain
* Tracking routes were defined for proposals and legislation processes,
but in the tracking section only investments were shown
* Probably many more things, since these issues were detected after only
an hour reviewing and testing the code

So we're removing this untested section before releasing version 1.1. We
might add it back afterwards.

config/routes/admin.rb

@@ -62,6 +62,9 @@ namespace :admin do
 
     resources :budget_investments, only: [:index, :show, :edit, :update] do
       member { patch :toggle_selection }
+
+      resources :milestones, controller: "budget_investment_milestones"
+      resources :progress_bars, except: :show, controller: "budget_investment_progress_bars"
     end
 
     resources :budget_phases, only: [:edit, :update]
@@ -103,11 +106,6 @@ namespace :admin do
     get :summary, on: :collection
   end
 
-  resources :trackers, only: [:show, :index, :edit, :update, :create, :destroy] do
-    get :search, on: :collection
-    get :summary, on: :collection
-  end
-
   resources :valuator_groups
 
   resources :managers, only: [:index, :create, :destroy] do
@@ -210,7 +208,8 @@ namespace :admin do
         member { patch :toggle_selection }
       end
       resources :draft_versions
-      resources :milestones, only: :index
+      resources :milestones
+      resources :progress_bars, except: :show
       resource :homepage, only: [:edit, :update]
     end
   end