Document changes to expert elasticsearch queries

Elastica seems to have fixed escaping elasticseach query strings, so expert elasticsearch queries that had date ranges (such as `updatedAt:[2014-03-23 TO *]` should work as of ES 7.10.2. One other change is that boolean values need to be `true` or `false` instead of `1` or `0` (such as `hasDigitalObject:true`). This should be updated in [expert searching docs](https://github.com/artefactual/atom-docs/blob/2.10/user-manual/access-content/advanced-search.rst#expert-searching-and-indexed-elasticsearch-fields)

Start with the expert searching and indexed Elasticsearch fields section in user-manual/access-content/advanced-search.rst. Review the existing date-range and boolean query examples, then update them to reflect Elasticsearch 7.10.2 behavior. Done means the documentation accurately shows date ranges and true/false boolean values.

Written by the indexing model from the issue text.