DORA metrics: Updated rating labels for performance badges

The rating levels for the performance badges have been updated. For each of the four DORA metrics, a four-level rating is provided based on the measured metric value for the last 3 months. The ratings are largely based on the 2019 State of DevOps Report with some modifications. As a result, the following labels are used:

• Elite - The measured value matches or exceeds industry-wide best practices. The goal should be to maintain the status quo.
• Good - The measured value is within the target range. A further improvement will still increase the engineering performance in this area.
• Ok - The measured value is below the target range. Improvements to the underlying processes are recommended to increase the engineering performance in this area.
• Needs focus - The measured value is clearly below the recommended target. It is recommended to inspect and improve the underlying processes to increase the engineering performance in this area.