Add Support for Grafana PDC

[oc-christopher-billett]

Is your enhancement related to a problem? Please describe.

Yes - Unable to use this datasource from Grafana Cloud when redis sits within a Private network

Describe the solution you'd like

Support the use of Grafana PDC (Private Data Connections) as is used by most other datasources

Describe alternatives you've considered

There is no alternative

Additional context

Running redis within a Private network without exposing it to the internet to connect to the Grafana Cloud is not possible.