UI/UX changes related to tracks

Add confirmed and cfp_active scopes to Track
Render markdown in track's description
Make the views more similar to the proposal/events views
Change the sequence of columns in admin/Tracks#index
Remove the short_name column from the index views
Add button "My Tracks" in the user menu
Fix track count in proposals
Add details of track in admin/Tracks#show
Use tabs to show track details and events

app/views/layouts/_user_menu.html.haml

@@ -12,6 +12,10 @@
     = link_to(conference_program_proposals_path(@conference.short_title)) do
       %span.fa.fa-comment
       My Submissions
+  %li
+    = link_to(conference_program_tracks_path(@conference.short_title)) do
+      %span.fa.fa-road
+      My Tracks
 %li
   - if ENV['OSEM_ICHAIN_ENABLED'] == 'true'
     = link_to(destroy_user_ichain_session_path, method: 'delete') do