[Monitoring] Read from metricbeat-* for ES node_stats

[chrisronline]

Relates to #73864

This PR adapts the UI code to read from metricbeat-* indices for queries against ES node_stats type monitoring documents while preserving existing functionality. This work is based off the changes done on the beats side (elastic/beats#19747) and must be used to test this PR. This PR should work outside of the beats PR, in that existing functionality shouldn't break at all (so it's safe to merge this to master without the beats PR going into master)

This is the first PR of several that will adapt the UI code to read from all monitoring document types, and as such, it comes with a little more code changes, mainly the changes necessary to ensure all queries start searching against metricbeat-* as well as handling the fact that type is not aliased.

To test:

1. Clear all existing monitoring data (to make it easier to test, you don't need to do this)
2. Pull down the beats feature branch
3. Enable the elasticsearch-xpack module and start Metricbeat.
4. Ensure you do not see node_stats in the response of this query:

POST .monitoring-es-*/_search
{
  "size": 0,
  "aggs": {
    "types": {
      "terms": {
        "field": "type",
        "size": 10
      }
    }
  }
}

5. Ensure you at least see node_stats in the response to this query:

POST metricbeat-*/_search
{
  "size": 0,
  "aggs": {
    "types": {
      "terms": {
        "field": "metricset.name",
        "size": 20
      }
    }
  }
}

6. Ensure the ES nodes list and ES node pages work properly

[elasticmachine]

Pinging @elastic/stack-monitoring (Team:Monitoring)

[chrisronline]

@elasticmachine merge upstream

[chrisronline]

@elasticmachine merge upstream

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 1412cf7

Build metrics

✅ unchanged

History

• 💚 Build #72271 succeeded bdc8eb2
• 💔 Build #71295 failed a7dbb30
• 💔 Build #70630 failed a1ddb6b

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[igoristic]

Everything works as expected. Great job!

[chrisronline]

Backport:

7.x: 8bde2b3