Superfluous metrics are being created from SmallRye internal classes

[jmartisk]

Classes in io.smallrye.metrics.interceptors package are annotated in a way that when scanned as application classes, some metrics will be created out of them, but these are internal classes and are not meant to be scanned for metric annotations. This means we register some metrics unnecessarily, which hinders performance and makes the export contain superfluous metrics whose values will always be 0. An excerpt from such bloated OpenMetrics export:

# TYPE application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_total counter
application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_total 0.0
# TYPE application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_rate_per_second gauge
application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_rate_per_second 0.0
# TYPE application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_one_min_rate_per_second gauge
application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_one_min_rate_per_second 0.0
# TYPE application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_five_min_rate_per_second gauge
application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_five_min_rate_per_second 0.0
# TYPE application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_fifteen_min_rate_per_second gauge
application_io_smallrye_metrics_interceptors_MeteredInterceptor_meteredMethod_fifteen_min_rate_per_second 0.0

This happens for every application that has MP Metrics enabled.