[CX] Add support to loading files for multiple prefixes

Currently, we provide a single prefix and load the files metadata under that prefix. With the support for computed fields for operators like IN operator, we can end up with multiple prefixes.

Example, given the following prefix user-data/{userid:int}

SELECT *

FROM userdata

WHERE user_id IN [1, 2]

The above translates to loading the data for the prefixes:

user-data/1

user-data/2