Feature/update urls and view endpoint

Create a url and endpoint for course site creation that responds to GETs and POSTs.  Create another url that shows a job status with a static template for now.  Create a mixin that retrieves a CourseData object and will raise a 404 if not found.  Create another mixin that uses the prior mixin to retrieve course data and will be the place to handle permission of whether the course creation can start.  Add test placeholders for mixins.