View closed epics on roadmap view

• Closed epics should appear in the roadmap view.
• Even though an epic is closed, you still want it on the roadmap view because likely you finished it. So if you move back in the timeline view of the roadmap itself, you want to see what you finished.

Proposal

Dropdown closed	Dropdown open

• There should be 16px margin between dropdown and elements on each side
• Options should be:
  • All epics
  • Open epics
  • Closed epics
• Preference should be stored per user