feat(opensearch): Add prometheus-exporter plugin to opensearch image

[labrenbe]

Description

Add the opensearch-prometheus-exporter plugin to the Opensearch image.

Definition of Done Checklist

Note

Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant.

Please make sure all these things are done and tick the boxes

• Changes are OpenShift compatible
• All added packages (via microdnf or otherwise) have a comment on why they are added
• Things not downloaded from Red Hat repositories should be mirrored in the Stackable repository and downloaded from there
• All packages should have (if available) signatures/hashes verified
• Add an entry to the CHANGELOG.md file
• Integration tests ran successfully

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

bake --product <product> --image-version <stackable-image-version>
kind load docker-image <image-tagged-with-the-major-version> --name=<name-of-your-test-cluster>

See the output of bake to retrieve the image tag for <image-tagged-with-the-major-version>.

[razvan]

LGTM.
Tested by:

• building the image locally
• importing it in local minikube cluster
• run the operator smoke test and from a pod shell:

stackable@opensearch-nodes-cluster-manager-0 /stackable/opensearch-3.1.0-stackable0.0.0-dev $ curl -k -u admin  https://opensearch:9200/_prometheus/metrics | head
Enter host password for user 'admin':
# HELP opensearch_indices_fielddata_memory_size_bytes Memory usage of field date cache
# TYPE opensearch_indices_fielddata_memory_size_bytes gauge
opensearch_indices_fielddata_memory_size_bytes{cluster="opensearch",node="opensearch-nodes-cluster-manager-0",nodeid="FdwQ9er3TRidMwIkBfa-6Q",} 0.0
# HELP opensearch_index_merges_current_number Current rate of merges
# TYPE opensearch_index_merges_current_number gauge
opensearch_index_merges_current_number{cluster="opensearch",index="my-dsl-index",context="primaries",} 0.0
opensearch_index_merges_current_number{cluster="opensearch",index=".opendistro_security",context="primaries",} 0.0
opensearch_index_merges_current_number{cluster="opensearch",index="my-dsl-index",context="total",} 0.0
opensearch_index_merges_current_number{cluster="opensearch",index=".opendistro_security",context="total",} 0.0
# HELP opensearch_cluster_inflight_fetch_number Number of in flight fetches