Frontend for epic start date and end date
- Sidebar in the epic to include start date and end date.
- There is no way for the user to select invalid dates in the date picker (similar to due date in issues): start date must be less than or equal to end date (Can be same day).
- Both fields are optional.
- Permissions for changing the fields are the same as the permissions for editing the title/description of the epic, as described in #3550 (closed).
- Ability to expand/collapse sidebar (similar to other sidebars)
- When collapsed, the behavior and information shown should be the same as milestone dates
|Expanded||Collapsed: empty||Collapsed: start only||Collapsed: finish only||Collapsed: start and finish|