Change alert panels

- move the alert panels (duplicate, out of scope) to be above the tabs
- change the styling to use the "callout" pattern from `govuk_admin_template`.
- make status display consistently across the need pages.

![image](https://cloud.githubusercontent.com/assets/23801/5144238/8c81e948-7190-11e4-973d-04aeaaa23235.png)

![image](https://cloud.githubusercontent.com/assets/23801/5144249/9fec2be2-7190-11e4-99f7-6605138f11a5.png)

/cc @fofr