[Kubernetes] Add state namespace datastream

[constanca-m]

What

Add state namespace data stream.

The metricset was added in version 8.11.0.

Dimensions for TSDB:

• kubernetes.namespace is unique, so it is a dimension.
• agent.id is a common dimension among data streams.
• orchestrator.cluster.url is a dimension for all kubernetes data streams.

Results from running TSDB testing kit:

The time series fields for the TSDB index are: 
	- dimension (3 fields):
		- agent.id
		- kubernetes.namespace
		- orchestrator.cluster.url
	- gauge (1 fields):
		- kubernetes.state_namespace.created.sec
	- routing_path (3 fields):
		- agent.id
		- kubernetes.namespace
		- orchestrator.cluster.url

Index tsdb-index-enabled successfully created.

Copying documents from .ds-metrics-kubernetes.state_namespace-default-2023.10.30-000001 to tsdb-index-enabled...
All 210 documents taken from index .ds-metrics-kubernetes.state_namespace-default-2023.10.30-000001 were successfully placed to index tsdb-index-enabled.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

How to test this PR locally

1. Clone this branch.
2. Build the package.
3. Update the service registry.
4. Add Kubernetes to a policy and check the new data stream.

Related issues

Relates to elastic/elastic-agent#3100.

Screenshots

In Discover:

In the integration itself:

[elasticmachine]

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Build stats

• Start Time: 2023-10-31T16:41:46.770+0000

• Duration: 77 min 5 sec

Test stats 🧪

Test	Results
Failed	0
Passed	97
Skipped	0
Total	97

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[elasticmachine]

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[gizas]

Another idea is to consider if we need to add this info of namespace in our dashboards. To add it in Overview or in Pods?

@MichaelKatsoulis , @tetianakravchenko , @ChrsMark suggestions?

[tetianakravchenko]

should here be defined metric_type ?

[constanca-m]

Since TSDB won't be enabled, then the metric type does not need to be defined.

[gizas]

Why would not be enabled?

[constanca-m]

The advantages of TSDB are related to the metric types. This data stream only has one metric type, so there wouldn't be any. We followed a similar approach for other data streams that only had one metric, such as AWS Billing or GCP Billing @gizas

[constanca-m]

After TSDB meeting discussion, we are enabling TSDB in all metric data streams after all. I updated the commits and will update the description now.

[elasticmachine]

Package kubernetes - 1.52.0 containing this change is available at https://epr.elastic.co/search?package=kubernetes

[elasticmachine]

Package kubernetes - 1.55.0 containing this change is available at https://epr.elastic.co/search?package=kubernetes