Escape forward slash (#7695)

This fixes [#7695](https://issues.dp.la/issues/7695), which noted an error parsing "Yale University, Cushing/Whitney Medical Library".  As Mark M. discovered, when we upgraded to the newer version of Elasticsearch, we also started using a new version of Lucene, which uses `/` as a reserved character.  This code escapes `/`.

This also fixes the following cuke which was previously failing:

`cucumber features/metacharacter_filtering.feature:27 # Scenario: Basic keyword search with embedded double-quote`

There are other metacharacter cukes that are still failing (see [#7676](https://issues.dp.la/issues/7676)), but they are beyond the scope of this ticket.