Tickets controller clean up.

Pushes instance variable setup for the ticket's search form into a
search presenter object. This reduces the noise in the tickets controller
and makes things at least marginally more meaningful by assinging the
responsibilities for setting up the search form variables to an object
dedicated to the search form. The "build_states" helper method that was
formerly in the the TicketsController has also been refactored a bit and
pushed to the TicketsHelper since it is a view/formatting related bit of code.