[receiver/elasticsearch]: add metrics related to GET operations

[aboguszewski-sumo]

Description:
New metrics have been added. However, I think that they're a bit troublesome to add. They are metrics that reflect how many GET operations ended up with success (exists), how many ended up with failure(missing) and time spent on these operations.
Currently (on main) only total sum of these two values is being sent as elasticsearch.node.operations.* metrics with get attribute. This is the main reason why I think that adding them is not easy. I thought up of two solutions that wouldn't be breaking changes:

• add another values to the existing attribute, eg. get_exists and get_missing - it would not be a breaking change, but I feel that it doesn't look good
• add another metrics, eg. elasticsearch.node.operations.get.* - it is not consistent with how other metrics are organised, but neither breaks anything. Might seem unintuitive, because then total count would be elasticsearch.node.operations.completed, but total success count would be elasticsearch.node.operations.get.completed.

I implemented the second one, but I'm open for discussion. If we don't mind breaking changes, then we could for example implement the first one and remove the total count, because exists + missing = total.

Link to tracking Issue: #14635

Testing:
Unit tests and integration tests.

Documentation:
Generated by mdatagen.

[djaglowski]

I agree with the general approach of adding a new metric here. The other metric is focused on the type of operations, whereas this new one is focused on the result of an operation.

[aboguszewski-sumo]

This seems outdated:
https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/9ee4a15478d8d579ad18621173984dd85cb30321/receiver/elasticsearchreceiver/scraper.go#L148
If I'm counting correctly, after adding these new metrics, there are 110 different Record* calls in scrapeNodeMetrics, but some are version dependent etc. so I'm not sure if it's the number we should add.

[aboguszewski-sumo]

Rebased after one test file has been removed.

[aboguszewski-sumo]

The metrics are now disabled by default.