Extracting common search methods to an specific interface
Producer based on runtime conditions + qualifier
Endpoint refactoring to support search services
Add reference to the real implementation because
I'm really bad at unit tests with OpenEJB
Inclusion of producer to provide in a single class
the current logged in username
Removal of duplicated argument from all methods.

In this commit:

- Removal of all the references to extractUsername
 at the endpoints
- Removal of duplicated references to HttpServletContext
- Make use of the producer to search by the current
 logged in user