Use similar interface to access gitolite

Simplified gitolite handle logic
Stubn over monkeypatch
Stub only specific methods in Gitlab:Gitolite
Moved grach auth to lib
added specs for keys observer
removes SshKey role

lib/tasks/gitlab/gitolite_rebuild.rake

@@ -16,7 +16,7 @@ namespace :gitlab do
     task :update_keys => :environment  do
       puts "Starting Key"
       Key.find_each(:batch_size => 100) do |key|
-        key.update_repository
+        Gitlab::Gitolite.new.set_key(key.identifier, key.key, key.projects)
         print '.'
       end
       puts "Done with keys"