Add cluster name mapping/aliasing support to Instana ArgoCD sensor for OpenShift GitOps compatibility

Problem Statement

When using OpenShift GitOps operator with Instana's ArgoCD sensor, there is a mismatch between the cluster name defined in ArgoCD (in-cluster - the default managed by OpenShift GitOps) and the actual Kubernetes cluster name in Instana (e.g., icp-sand).

The ArgoCD sensor requires exact cluster name matching for the Platforms > Kubernetes integration to display ArgoCD statistics. 

This creates a conflict because:

• Renaming the ArgoCD cluster connection to match Instana breaks OpenShift GitOps operator management
• The operator automatically creates and manages the default in-cluster connection
• Manually managing cluster connections is operationally burdensome and defeats the purpose of using the operator

Current Behavior

com.instana.plugin.argocd:
  enabled: true
  url: 'https://<argocd-server-address>'
  username: instana
  password: '<redacted>'
  clusters: [in-cluster]  # ArgoCD cluster name

When ArgoCD cluster name = in-cluster but Instana sees cluster as icp-sand, the Platforms > Kubernetes page does not show ArgoCD sync status and statistics.

Desired Behavior

Support cluster name mapping in the ArgoCD sensor configuration:

com.instana.plugin.argocd:
  enabled: true
  url: 'https://<argocd-server-address>'
  username: instana
  password: '<redacted>'
  clusters: [in-cluster]
  cluster_mapping:
    in-cluster: icp-sand
    other-argocd-cluster: actual-k8s-cluster-name

OR support label-based matching:

com.instana.plugin.argocd:
  enabled: true
  url: 'https://<argocd-server-address>'
  username: instana
  password: '<redacted>'
  cluster_matching:
    type: label
    label_key: cluster.instana.io/name

Affected Components

• Instana Agent ArgoCD sensor plugin
• Platforms > Kubernetes UI integration
• ArgoCD sensor configuration schema