Delete a service

- Puts a delete button at the bottom of every summary page
- Button takes supplier to same page with banner and button at top asking if they want to confirm deletion
- When deleted the user is sent back to dashboard

**Note: needs `grunt dev` running for styling of new banner to appear**
There is currently a problem with retrieval/display of some strings containing apostrophies, and this button is one of those places (e.g. for a service with Service Name "Kev's Service" the button displays only:
  Yes, delete "Kev
(which is a trifle disconcerting if your name happens to be Kev).
But this is already flagged as a wider bug so I'm tempted to merge this and leave it to the bug fix to get the button to display properly for strings with an apostrophe.