Pagination kaminari

Add pagination to listings using [kaminari gem](https://github.com/amatsuda/kaminari).

Translation to spanish is also done. If you don't like it you can look at the end of the file config/locales/es.yml

By default I configured it to show 10 circles per page. It can be changed from config/initializers/kaminari_config.rb

It needs some esthetic changes that is why I left app/views/kaminari/* files in the repository (@davilious please, could you do your magic?) :smile: