Refactor DAO usage

Currently, RangerDaoManagerBase is used to construct new DAO instances, instead of relying on Spring to provide one for it. This would reduce the code to write and run, and make it less interdependent, and simplifies the tests, as less code would be needed to mock.

 As RangerDaoManagerBase is used everywhere, and to avoid having huge patches, it would be better do it in smaller steps.