Add a vertical header control to the dashboard

[cccs-jc]

Is your feature request related to a problem? Please describe.
Be able to put headers on the left/right vertically. It helps saving space on really crammed dashboards.

Describe the solution you'd like
A new control in the dashboard UI to create vertical headers.

Describe alternatives you've considered
We have a work around which involves putting html and css code in the markdown slice. However this solution is not very intuitive to use.

Additional context
This is what a dashboard with horizontal header and a custom markdown displaying vertical text. But a better solution would be to have a native vertical header.