Context:

Elasticsearch offers the ability to create "auto-interval date histrograms" which let you specify a number of buckets. ES then chooses the bucket unit that best achieves this amount of buckets. 

We can use this type of histogram instead of our current automatic interval aggregation creation (see DateAggregationService.createAutomaticIntervalAggregationWithSubAggregation) where we manually calculate the exact bucket interval needed to create 80 buckets, lets refactor this to use auto-interval date histrograms instead 

Docs: https://www.elastic.co/guide/en/elasticsearch/reference/7.x/search-aggregations-bucket-autodatehistogram-aggregation.html 

AT:

• date reports with automatic units use auto-interval date histograms with bucket number set to NUMBER_OF_DATA_POINTS_FOR_AUTOMATIC_INTERVAL_SELECTION