Changes

tsk67 Moves pagination to a separated method on service
Refactorizes the story service class to extract the pagination from
various methods and takes it to a separated method, making it more
readable and reusable. This new method accepts two querys, one for
getting the results and other for the results count, number of page and
number of max items per page. Also the method is overloaded for accept
SQL strings without parameters, with the same parameter for the results
query and for count query, or with different parameters for each query.
This parameters are expected to be received as unary operator to be
applied on the query.