Create BaseController

This allows common functionality (authorization and db context) to be
housed in a central location.
Make TicketsController Authorize by default
Remove TicketController/Create

This is handled better in the Projects controller.
Secure TicketsController

Using the new Authorizations per project, TicketsController now denies
requests that come from users that don't have proper permissions.
Secure ProjectsController
Remove redundant Authorize attribute