Improve the Draft Decision interface

Is your feature request related to a problem? Please describe.
Currently, when a Draft Decision is made, the email link an editor receives takes you to 'add a new draft' alongside 'existing drafts'. This is confusing, as you would expect for the editor to be taken to the draft itself. Although the existing drafts are listed down the right-hand side bar this also makes it difficult to know whether you are editing a draft or adding a new draft.

Describe the solution you'd like

1. for email links to draft decisions, take the editor directly to the draft decision as opposed to the add a new DD page.
2. for the interface itself to be clarified - perhaps a separate initial DD page that contains all drafts and a button to add a new draft, which takes the user to another page with the 'add a DD' text boxes etc.

Start by tracing the email link for a Draft Decision and the interface it opens. Review how existing drafts and the add-new-draft form are presented, then confirm the intended navigation and page separation with a maintainer. Done means the email opens the selected draft and the interface clearly distinguishes existing drafts from creating a new one.