Support scheduling options / cumulative evaluation window on DatadogMonitor

Support scheduling options / cumulative evaluation window on DatadogMonitor: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). I'm using the operator to manage monitors via GitOps. I'd like to set up a few "calendar-aligned" cumulative monitors — e.g. a monthly cost…

The task

I'm using the operator to manage monitors via GitOps. I'd like to set up a few "calendar-aligned" cumulative monitors — e.g. a monthly cost / usage budget alert that resets on the 1st of each month, and a daily SLO-like accumulator that resets at 00:00 UTC.

Part of FineEnvs/MiMo-V2.6-RL-harbor-code.