Add "edit publication" link to pub page, linking to pub dashboard #1

Right now we have an edit button (pencil in upper right, button at bottom) if viewing a published post where you're authed as the creator.

Let's add a similar thing for publication homepage — if you're logged in and viewing your own pub, you should have an easy link to edit!

This could also be pencil icon in the upper right, or maybe replace the 'subscribe' section with larger 'Edit Publication' button with that icon, centered.