Ability to add subheadings / dividers between long lists of stories

[fbuys]

https://ombulabs.atlassian.net/browse/DT-255

Before we start...:

• [x] I checked the documentation and didn't find this feature
• [x] I checked to make sure that this feature has not already been requested

Branch/Commit:

Commit: 432aef33017866df594fca0469d2899dfe803da5

Describe the feature:

As an estimator When I have a long list of stories I would like to add sub-titles/labels/dividers to make it visually clearer and to visually group stories

Problem:

As a estimator When I have a long list of stories The long list of stories become like a see of text By grouping the stories it might be possible to convey addition context to the other project viewer.

I will abide by the code of conduct