[detectors/ibmcloud/classic] Contribute ibmcloud classic detector from resourcedetectionprocessor #8963

Problem Statement

collector-contrib/processor/resourcedetectionprocessor/internal/ibmcloud/classic implements a resource detector for IBM Cloud Classic Infrastructure (SoftLayer) virtual machines. There is currently no equivalent in go-contrib/detectors/, which means IBM Cloud Classic detection is only available to collector-contrib pipelines and not to any Go SDK user.

Proposed Solution

Add a new detectors/ibmcloud/classic package implementing the IBM Cloud Classic detector as a resource.Detector, ported from the collector-contrib implementation, so that collector-contrib/processor/resourcedetectionprocessor can delegate to it and any other Go SDK user can adopt it.

Prior Art

• Collector-contrib implementation to port from: processor/resourcedetectionprocessor/internal/ibmcloud/classic
• Tracking issue: [processor/resourcedetection] Align detectors with opentelemetry-go SDK detectors opentelemetry-collector-contrib#48159

Additional Context

What the collector-contrib detector does:

• Queries the IBM Cloud Classic (SoftLayer) Resource Metadata Service.
• Emits: cloud.provider (ibm_cloud), cloud.platform (ibm_cloud_classic_virtual_server), cloud.region, cloud.account.id, cloud.availability_zone, host.id, host.name, host.type.