This enables a more natural way of interacting with result sets,
and re-introduces in Doctrine DBAL a feature that has been available
in PDO from the begining.

DDC-217 - Refactor result caching to use a value object for all the important information which simplifies the code considerably and makes caching more powerful.

DDC-217 - Refactor result cache again to be much simpler, previous approach was too complicated and something like this needs longer testing. Now only caching the full result.