Directly index chant metadata from CantusDB

The goal of this issue is to reduce the duplication of CantusDB data in a separate Cantus Ultimus database that needs to be batch updated in order to pull data new/updated data from CantusDB.

In short, this issue involves saving folio-image mapping on Cantus Ultimus, but otherwise indexing, but not saving in a database, the rest of the chant-related data currently imported from CantusDB into our postgres database. This indexing should then occur on some schedule so that fixes and updates in CantusDB are propagated to Cantus Ultimus.