Add list all districts feature

- Add District domain class and District.hbm.xml file
- Add DistrictService interface and class
- Add required bindings in NInjectDependencyResolver class
- Add DistrictController with attributes for verifying user and session
- Add List view and ListViewModel class
- Add service and controller unit tests
- Create new district from jurisdiction name and type or update existing one when saving project details
- Refactor code