closes#5317
- Adds back button to steps 2 and 3
- Prevents user navigating from step 1 to step 3 unless blog has been created
- Prevents user navigating from step 2 to step 3 unless blog has been created
No issue
- Prevent download count ajax request from running forever, even after setup is complete.
- Remove unneeded setup routes and controllers.
- Refactor to use ES6-imported ajax.
- Refactor to use injected services.