Function parseAdvancedSearchQuery

Parse a JSON-serialized advanced search query into an include query and an exlude query. The structure of the query must be one of the following:

• Include only: A single non-NOT query
• Exclude only: A single NOT query
• Both exclude and include: A single NOT query AND'ed with a single non-NOT query

The behavior of this function is unspecified if the JSON has any other structure.

Returns

A tuple of an include query and an exclude query, parsed from the json. Either or both may be null.