Adding the ElasticInfraMetricsProcessor

[ishleenk17]

Description:

Currently, the ElasticInfraMetricsprocessor code is present in this branch (approved and merged).
Move the ElasticInfraMetricsprocessor Code to the Components Repo.
This Processor will be using the elastic/opentelemetry-lib for the translations of metrics from Hostmetrics to System.

The Collector Config will look like below with the processor:

receivers:
  hostmetrics:
    collection_interval: 30s
    scrapers:
      load:
processors:
  resourcedetection/system:
    detectors: ["system", "ec2"]
  elasticinframetrics:
    add_system_metrics: true

exporters:
...............

service:
  pipelines:
    metrics/host:
      receivers: [hostmetrics]
      processors: [resourcedetection/system, elasticinframetrics]

Relates: https://github.com/elastic/opentelemetry-dev/issues/250

Testing:

This processor code has been tested by building a custom collector. The translated metrics are flowing in, confirming that the processor is working correctly.

[ishleenk17]

As discussed with @rogercoll , this PR adds the code for the ElasticInfraMetricsProcesor. The addition of component to the distro will be done as a separate PR.

[rogercoll]

LGTM, just a couple of follow up comments that can be addressed in a future PR

[ChrsMark]

Thank's for adding the tests!