BDD: Update structure to for the inheritance fix

This belongs to a inheritance fix that involve:
- [x] ezsystems/BehatBundle#1
- [x] ezsystems/ezpublish-community#154
- [x] ezsystems/ezpublish-kernel#872 (EzPublishLegacyBundle and EzPublishRestBundle)
- [x] ezsystems/DemoBundle#90

Todo:
- [x] change classes namespaces to reflect changes
- [x] remove unneeded paths

**Needs to pass on travis**:
- [x]  ezsystems/ezpublish-community#163