This also caught and fixed an issue where the enum index is not
sequential :/
No error enums have been defined on the service side yet so it's
possible to modify the enum index directly.
There is no behavior change.
This groups utilities into two modules:
- `transformation.ts`: for any logic related to mutating / filtering of
the names, values of telemetry entries.
- `metricsRegistry.ts`: for any logic that related to the maintenance of
metrics.json files.