[VSA] Add Overview stage to VSA

Overview

As part of the FY22 vision, we will be adding DORA metrics to Value Stream Analytics so that users can evaluate their software delivery performance using industry standard metrics. The DORA metrics will be displayed in an Overview stage in the horizontal stage navigation within a value stream. As an MVC, we need to create the Overview stage.

Proposal

• Add an Overiew stage as shown in #246493 (closed)
• Add a home icon to the Overview stage in the path component

• In the overview stage, hide the stage table
• Only display the charts and metrics on the overview stage. For now, we will use the Time and Recent Activity metrics until we have implemented DORA metrics.