We need to limit the search request aggregations to whole multiples
of the configured interval for both histogram and date_histogram.
Otherwise, agg buckets won't overlap with the rolled up buckets
and the results will be incorrect.
For histogram, the validation is very simple: request must be >= the config,
and modulo evenly.
Dates are more tricky.
- If both request and config are fixed dates, we can convert to millis
and treat them just like the histo
- If both are calendar, we make sure the request is >= the config with
a static lookup map that ranks the calendar values relatively. All
calendar units are "singles", so they are evenly divisible already
- We disallow any other combination (one fixed, one calendar, etc)
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