Add Custom Membership Provider

- Remove UserService interface and class
- Update User class to inherit MembershipUser
- Update CustomMembershipUser class to inherit MembershipProvider
- Add membership settings to config files
- Add CustomerMemberhipProvider unit tests
- Add CreateViewModel for Edit view
- Change database and other files to accommodate the changes
- Add AccountController and IAuthProvider, FormsAuthProvider, LoginViewModel and unit tests for Login and Logout features
- Refactor all unit tests