[reporting] combine usage requests

[jbudz]

Discussed briefly with @tsullivan, we can likely combine these requests https://github.com/elastic/kibana/blob/master/x-pack/plugins/reporting/server/usage/get_reporting_usage_collector.js#L129

[elasticmachine]

Pinging @elastic/kibana-app

[tsullivan]

In the current code, there are 3 queries, which each get job type data for a block of one of 3 time ranges: last 7 days, last 1 day, all time.

We can replace the 3 queries with one that uses a filters aggregation, and it will fetch the same data:

POST /.reporting-*/_search
{
  "size": 0,
  "aggs": {
    "date_ranges": {
      "filters": {
        "filters": {
          "last7": {
            "range": {
              "created_at": {
                "gte": "now-7d/d"
              }
            }
          },
          "last1": {
            "range": {
              "created_at": {
                "gte": "now-1d/d"
              }
            }
          },
          "all": {
            "match_all": {}
          }
        }
      },
      "aggs": {
        "jobTypes": {
          "terms": {
            "field": "jobtype",
            "size": 3
          }
        },
        "objectTypes": {
          "terms": {
            "field": "meta.objectType.keyword",
            "size": 3
          }
        },
        "layoutTypes": {
          "terms": {
            "field": "meta.layout.keyword",
            "size": 3
          }
        },
        "statusTypes": {
          "terms": {
            "field": "status",
            "size": 4
          }
        }
      }
    }
  }
}

[tsullivan]

PR upcoming: #34327