Add per-period deploy frequency to Value Stream Analytics

Overview

Our vision for Value Stream Analytics uses lead time, cycle time, deploys, and defects as the primary measurements of a highly functioning process for delivering software. We're adding cycle time and lead time in a separate issue; we should also plan to add per-period deploy frequency.

Proposal

On group-level Value Stream Analytics:

• Add a panel for "Daily deploys" as the left-most panel. This figure should be calculated as average deploys per day, and adjusted appropriately based on the timeframe selected in the UI (7/30/90 days).
• Re-name "Deploys" as "Deployment count" and move it to the left of "New issues" so it is the middle panel.

Out of scope

More panels will be added in the future:

Panels will be clickable in the future, for more detail and to be visualized over time.