Oncosts: obtain salary scale data from CHRIS

This issue is to track the possibility of using CHRIS as a source for importing salary scale data.

Note

If this is possible, then uis/devops/research/research-dashboard/ucamstaffoncosts#41 and #13 are likely to be reduced in scope or unnecessary

Discussions with Steve Smith and Dean Johnson have established that, with the CHRIS data mart likely to be replaced by a Fabric lakehouse, then the Lakehouse's GraphQL API may end up being the best source for this data.