Add health endpoint to Splunk HEC receiver

[atoulme]

Is your feature request related to a problem? Please describe.

The Splunk HEC endpoint usually allows to set a health endpoint, located under /services/collector/health, which returns 200 if the service is up, and may return other status codes such as 503 if there is a need for backpressure.

Describe the solution you'd like

This enhancement should aim to support adding a simple health endpoint returning 200 if queried.

Describe alternatives you've considered

No response

Additional context

No response

[github-actions]

Pinging code owners: @atoulme @dmitryax. See Adding Labels via Comments if you do not have permissions to add labels yourself.

[github-actions]

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Pinging code owners:

• exporter/splunkhec: @atoulme @dmitryax

See Adding Labels via Comments if you do not have permissions to add labels yourself.