Restructure modules packages so that all auto-configuration is
organized under single top-level autoconfigure package.
Issue: 46071
Co-authored-by: Andy Wilkinson <andy.wilkinson@broadcom.com>
Add a new `ObservationHandlerGroup` interface that allows grouping
logic to be implemented by the metrics and tracing modules. This
update removes the need for `ObservabilityAutoConfiguration`.
Issue: 45746