Currently this is not a configurable item. I'd suggest submitting an enhancement request. You can access this via the "Ideas" lightbulb icon at the top right of this page.
If you're not on IEM 2017 yet - you may want to set up a test server of IEM 2017 and request SU1 from support.
There's a wholly re-done policy portal that you can customise a lot easier, which may give you more of the stuff you're looking at (leaving Workspaces more for the 'folks who need stuff beside a soft dist portal').
The new policy portal has an agent setting where you can configure the look & feel of it (including corporate branding) ... while the default "black on gray" is a bit bland, you can make it look VERY swoosh & modern with just a few changes (such as a kick-ass background, and high-resolution logos for your applications / packages which will scale automatically) .