Expose the metrics port according to the OTEL Collector config

[iblancasa]

If somebody creates an OpenTelemetry Collector instance with the following configuration:

apiVersion: opentelemetry.io/v1alpha1
kind: OpenTelemetryCollector
metadata:
  name: deployment
spec:
  mode: deployment
  config: |
    ...
    service:
      telemetry:
        metrics:
          level: detailed
          address: 0.0.0.0:9090
      pipelines:

The metrics port endpoint will be 9090 instead of 8888 (the default one). The operator will expose the 8888 without taking into account the user configuration:

opentelemetry-operator/pkg/collector/reconcile/service.go

Lines 197 to 200 in 56f5de9

	Ports: []corev1.ServicePort{{
	Name: "monitoring",
	Port: 8888,
	}},

Note
This issue was created from this thread.