UX: Consistent edit/delete buttons

The edit/delete UX for updates, tasks, and threads is a bit inconsistent atm. E.g. To delete an update you need to go edit -> delete, whereas for tasks there is a delete link at the bottom of the task. And the ‘edit’ button on updates does not match the design of the edit button on tasks/threads.

1. Decide on consistent approach
2. Implement for updates/tasks/threads