[FEATURE] Data Store record retention policy

**Is your feature request related to a problem? Please describe.**
The Data Stores feature provides a useful solution for synchronizing processes across multiple workflows. In this use case, data is added to a store or modified, but doesn't need to be stored in perpetuity -- however viewing data for some period after the fact can be useful for debugging purposes. Data Stores now has a storage limit, so cleaning up these rows needs to happen eventually to avoid surpassing this limit.

**Describe the solution you'd like**
I'd like the ability to set a retention policy on a per-data store level, so that records will be automatically deleted some number of days after creation or last modification, conserving the storage quota.

**Do you have a workaround?**
Records can be deleted manually, or one could create a cronjob to clean up old entries.