Major improvements to menu system and user authorization and access control

- Renamed Ubersmith references to Helpdesk, preparing for Salesforce integration
- Converted menu system to middleware, menu loaded per request based on roles
- Added middleware to roleManager to populate currentUser.roles,
   **not used for authorization**, authorzation should be done through authenticator.roleManager.can('action')
Merge pull request #157 from johann8384/menu_redesign

Major improvements to menu system and user authorization