[BUG]: Refresh tokens cleaned up too slowly

[chrisburr]

In DIRACGrid/diracx-charts#222 refresh token clean up was intended to be implemented by calling TRUNCATE on partitions which are too old.

Instead old refresh tokens are being cleaned with a simple DELETE which has two issues:

• A huge number of rows are deleted in each query, resulting in a massive undo log and poor performance
• Newer partitions aren't being maintained

Instead we should:

• Call TRUNCATE on old partitions and drop them
• Create new partitions if the next two years worth of partitions don't exist
• Add clean up to the DeviceFlows and AuthorizationFlows tables