There are several breaking changes related to the new performance audit prioritization that we should consider to clean up our JSON results:

• Create an explicit group to contain all performance diagnostics. All performance diagnostics have no group right now because the group is technically auto selected by the report renderer.
  • Consider renaming "Diagnostics" to "Insights"? Too much backporting/churn to be worth it
• Deprecate, but keep the overallSavingsMs (as metricSavings exists now)
• Remove metrics-to-audits.js
• Probably remove the opportunity details type