Added admin/admin user to cleandb.sql and also a cellink for it

Additionally removed `use agrodb_for_tests` because when we apply
script using `mysql dbname < cleandb.sql` we already specify the DB to
work with.
#49 Added Spring MVC and first controller

- Added Spring MVC dependency into Maven.
- Added SpringDispatcher (Front Controller) to web.xml so that it
 intercepts requests and chooses a controller that's responsible for
 the request handling.
- Implemented a simple CellinkController that just outputs the cellink
 name by its id. Old CellinkNameServlet is to be removed.
- Added a simple JSP into WEB-INF that outputs the information passed
 from Controller.