JSON support

JSON support in Fabric Datawarehouse enables processing of textual data formatted as JSON text. The new JSON features in Fabric DW are:* FOR JSON query option that formats the query results as JSON text. This was one of the features that is requested on Microsoft Fabric Idea site.* JSON scalar functions that can also be used in Azure SQL database. In addition to the existing JSON scalar functions (ISJSON, JSON_VALUE, JSON_QUERY, and JSON_MODIFY), Fabric DW is suporting the latest JSON functions that exist in Azure SQL Database - JSON_PATH_EXISTS, JSON_OBJECT, and JSON_ARRAY.