Issue board sidebar

## What does this MR do?

Adds a sidebar when clicking an issue in the issue boards lists. This allows user to easily update other parts of the issue details without having to visit the issue itself. Same functionality as on issue page.

When creating a new issue the sidebar automatically opens.

## Screenshots (if relevant)

![Screen_Shot_2016-10-07_at_13.10.16](/uploads/ad08785f407d8ac3fe9cb078868a7839/Screen_Shot_2016-10-07_at_13.10.16.png)

## What are the relevant issue numbers?

Closes #21219

See merge request !6690