EZP-23163: Changed configuration parsing and mapping to use the new ConfigurationProcessor

https://jira.ez.no/browse/EZP-23163

See https://github.com/ezsystems/ezpublish-kernel/pull/931

* Adapted semantic configuration and mapping
* Changed minimum-stability `dev` to take advantage of the last changes in `ezpublish-kernel` for tests
* Removed PHP 5.3 from `.travis.yml` as `ezpublish-kernel` doesn't test it any more.