Use composite agg on date_histogram aggs in Monitoring UI code

[ycombinator]

The Monitoring UI code uses timeseries charts in several places. As such it makes heavy use of the date_histogram aggregation. Occasionally, if the interval of this aggregation is set to something too granular, the ES query errors out with an error like this:

{
      "took" : 3354,
      "timed_out" : false,
      "_shards" : {
        "total" : 7,
        "successful" : 5,
        "skipped" : 0,
        "failed" : 2,
        "failures" : [
          {
            "shard" : 0,
            "index" : ".monitoring-xxxx-7-2019.05.07",
            "node" : "xxxxxxxx",
            "reason" : {
              "type" : "too_many_buckets_exception",
              "reason" : "Trying to create too many buckets. Must be less than or equal to: [10000] but was [10001]. This limit can be set by changing the [search.max_buckets] cluster level setting.",
              "max_buckets" : 10000
            }
          },
          {
            "shard" : 0,
            "index" : ".monitoring-xxxx-7-2019.05.08",
            "node" : "xxxxxxxx",
            "reason" : {
              "type" : "too_many_buckets_exception",
              "reason" : "Trying to create too many buckets. Must be less than or equal to: [10000] but was [10001]. This limit can be set by changing the [search.max_buckets] cluster level setting.",
              "max_buckets" : 10000
            }
          }
        ]
      },
      "hits" : {
        "total" : {
          "value" : 0,
          "relation" : "eq"
        },
        "max_score" : null,
        "hits" : [ ]
      },
      "aggregations" : {
        "check" : {
          "buckets" : [ ]
        }
      }
    }

One solution to this might be to wrap the date_histogram aggregation in a composite aggregation.

[elasticmachine]

Pinging @elastic/stack-monitoring

[chrisronline]

I'm going to close this since the ask is too general. We already have addressed this in a few key places and will continue to make these changes as necessary