[Feature] - Replace OpenCensus metrics with OpenTelemetry metrics

[heiko-holz]

In order to replace the OpenCensus-to-OpenTelemetry-shim with native OpenTelemetry (OTEL) support (see #1336), we need to replace OpenCensus (OC) "metrics" by OTEL metrics.

For this feature, all OC metric dependencies should be removed and replaced by OTEL dependencies.