Research what start/end date to use on the "other" milestones

User story

As a [user]
I want [a start and end date that makes sense on all possible options in the Milestone dropdown]
So that [my charts make sense]

Tasks

• Research the best way to display for offical milestones
• Research the best way to display for the "All issues" and "no milestone issues"

Acceptance criteria

• All start and end dates make sense all burndown charts.

Notes