Visually depict Value Stream Analytics stages as a flow (Group level only)

Problem

As we start to realign value stream analytics as a flow, we should arrange our stages to visually depict a value chain. Our current approach reads top-to-bottom, which doesn't really depict a linear flow.

Proposal

Above the main container on the Value Stream page, add the standard, out of the box stages as chevrons. Notes:

• Overview should represent the current "Total" stage as a sum of all other stages.
• Subtitle of each container should be the median time spent.
  • Note that this does mean we're duplicating information on this page after this iteration.
• Include all active stages in horizontal navigation
• Add horizontal navigation behind feature flag value_stream_analytics_path_navigation