Email templates: drag into folders and a menu on every row

Email templates now work like Campaigns and Lists.

• Drag to file. Drag a template onto a folder in the rail to move it there, or onto Unfiled to take it out.
• A menu on every row. The ⋯ button has Open, Duplicate, Archive, Delete and Move to folder.
• Archived templates. Archiving hides a template from the library and the template picker without deleting it. Tick Archived to see them and unarchive.
• Duplicates stay together. A copy lands in the same folder as the original.