feature request (port-data): allow passing field sort direction when creating an index

[TillaTheHun0]

Our data service API is mostly based on Mango CouchDB. When creating an index, fields follows the sort syntax. Right now, we only allow fields as a string[], but also allowing specifying direction of each field in the index may be desirable. So fields could be:

Example, sorting by 2 fields:

[{"fieldName1": "DESC"}, {"fieldName2": "ASC" }]

Example, sorting by 2 fields, assuming default direction ("ASC") for both :

["fieldNameA", "fieldNameB"]