OCI: manage persistence directory

[srenatus]

Currently, we're putting "stuff" in "$persistence_path}/oci" or "/tmp/oci" (OS-dependent, some temp dir); but we're never cleaning it up.

1. Figure out if it needs to be cleaned up; and how large it could become if not cleaned up.
2. Do it automatically.

(2.) could be a periodic cleanup task for long-running OPA instances, I suppose.

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[stale[bot]]

This issue has been automatically marked as inactive because it has not had any activity in the last 30 days.