This commit changes the format of the `hits.total` in the search response to be an object with
a `value` and a `relation`. The `value` indicates the number of hits that match the query and the
`relation` indicates whether the number is accurate (in which case the relation is equals to `eq`)
or a lower bound of the total (in which case it is equals to `gte`).
This change also adds a parameter called `rest_total_hits_as_int` that can be used in the
search APIs to opt out from this change (retrieve the total hits as a number in the rest response).
Note that currently all search responses are accurate (`track_total_hits: true`) or they don't contain
`hits.total` (`track_total_hits: true`). We'll add a way to get a lower bound of the total hits in a
follow up (to allow numbers to be passed to `track_total_hits`).
Relates #33028
This changes the RollupSearch endpoint to proactively resolve index
patterns. If the index pattern(s) match more than one rollup index,
an exception is throw as before. But if the pattern only matches one
rollup index, execution is allowed to continue (unlike before where
it would assume all patterns were for raw data).
This also allows the search endpoint to resolve aliases that point to
a rollup index.
Also tweaks the documentation to make this clear.
Closes#34828
