Add opensearch metrics to Photon

Ref
- https://github.com/entur/photon/tree/henrik/opensearch-metrics
- komoot/photon#970

```
opensearch_cluster_health_status{application="Photon"} 1.0
opensearch_cluster_shards_active{application="Photon"} 5.0
opensearch_cluster_shards_relocating{application="Photon"} 0.0
opensearch_cluster_shards_unassigned{application="Photon"} 5.0
opensearch_documents_count{application="Photon",index="photon"} 2755611.0
opensearch_index_size_bytes{application="Photon",index="photon"} 6.79599092E8
opensearch_indexing{application="Photon",index="photon"} 0.0
opensearch_indexing_time_millis_milliseconds{application="Photon",index="photon"} 0.0
opensearch_search{application="Photon",index="photon"} 95.0
opensearch_search_time_millis_milliseconds{application="Photon",index="photon"} 157.0
```

Author: henrik242

.github/workflows/build-photon.yml

@@ -26,7 +26,7 @@ on:
         description: 'Photon JAR URL'
         required: false
         type: string
-        default: 'https://github.com/entur/photon/releases/download/cpu-metrics/photon-0.7.0.jar'
+        default: 'https://github.com/entur/photon/releases/download/opensearch-metrics/photon-0.7.0.jar'
 
 run-name: "Photon: ${{ inputs.build || 'Scheduled full import' }}${{ startsWith(inputs.build, '🚀') && format(' (tag: {0})', inputs.photon_image_tag) || '' }}"