fix: set GO usage environment variables from resource limits

[rogercoll]

No description provided.

[rogercoll]

All variables remain and GOMAXPROCS value is rounded up:

Environment:
      OTEL_K8S_NODE_NAME:   (v1:spec.nodeName)
      OTEL_K8S_NODE_IP:     (v1:status.hostIP)
      OTEL_K8S_NAMESPACE:  opentelemetry-operator-system (v1:metadata.namespace)
      OTEL_K8S_POD_NAME:   opentelemetry-kube-stack-daemon-collector-9brfc (v1:metadata.name)
      OTEL_K8S_POD_IP:      (v1:status.podIP)
      ELASTIC_AGENT_OTEL:  true
      GOMEMLIMIT:          1025MiB
      ELASTIC_API_KEY:     <set to the key 'elastic_api_key' in secret 'elastic-secret-otel'>   Optional: false
      ELASTIC_ENDPOINT:    <set to the key 'elastic_endpoint' in secret 'elastic-secret-otel'>  Optional: false
      GOMAXPROCS:          2 (limits.cpu)

[lahsivjar]

LGTM! One nit regarding hard coded mem limit.

[lahsivjar]

Maybe we can write a script to keep this 90% (or lower if we want to go lower) of the memory limit? Will be a bit easier to manage and update in future.

[rogercoll]

Definitely, that would be a better setting. As discussed, we can help with open-telemetry/opentelemetry-collector-contrib#30289 moving it forward.