User story: As a Wikipedia Library staff member, I want to decline a suggestion, so that I can notify the submitter that we will not be pursuing this partnership for a specific reason.

Sometimes suggestions come in which we can't or won't fulfil for some reason. This might be because the content is already open access, or because the content is not suitable for the library in some way. In these cases we would like to be able to decline (delete) the suggestion, while sending the suggester an email.

On the suggest page, an extra button should be present, but only for users with the staff flag. The button should say 'Decline' and be red, to indicate a destructive action.

When clicking decline, a popup should allow the user to write some text explaining why the suggestion has been declined.

The suggestion should then be deleted, and the following email should be sent to the suggestor:

Hi,

Thanks for making a partnership suggestion for The Wikipedia Library!

Your suggestion has been reviewed and declined for the following reason:

[REASON]

The Wikipedia Library team

[REASON] should be the text inputted by the staff member when declining.