chore: adopt kubernetes dql

[Kirdock]

Introduction

Added three different optional filters to the kubernetes DQL query via the additionalFilter placeholder.

• The namespace is now compared with the component annotation backstage.io/kubernetes-namespace. For non-kubernetes queries the metadata namespace is used and fallback to default. The following filter is added | filter namespace.id == "{namespace}"
• The kubernetes id is now compared with the component annotation backstage.io/kubernetes-id. The optional filter is added via | filter workload.labels[`backstage.io/kubernetes-id`] == "{kubernetesId}"
• The kubernetes label is now compared with the component annotation backstage.io/kubernetes-label-selector. The annotation label1=value1,label2=value2 will resolve to to | filter workload.labels[`label1`] == "value1" AND workload.labels[`label2`] == "value2"

Also

• One of the labels backstage.io/kubernetes-id, backstage.io/kubernetes-label-selector is now required for the kubernetes query
• If a kubernetes-label-selector is given, the kubernetes-id is ignored.
• Removed the component namespace fallback to default for kubernetes queries. We want to query all namespaces if nothing is defined.

:heavy_check_mark: Common checklist

• [x] Added tests for new functionality and regression tests for bug fixes
• [ ] Screenshots of before and after attached (for UI changes)
• [ ] Added or updated documentation (if applicable)
• [ ] Helpful resources linked (if applicable)

[Kirdock]

@Kirdock can you please update the documentation to reflect the changed and new behavior here: https://github.com/Dynatrace/backstage-plugin?tab=readme-ov-file#kubernetes-use-case

Already on it 👍