[chore] move process metrics to the registry

[trisch-me]

Replacement for #681 which is stale and outdated

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.

[braydonk]

Thanks for picking this up.