<feature>[kvm]: add periodic cleanup for expired VM host files

Add a periodic cleanup task that runs every 30 minutes to clean up
expired VM host files and backup files. Implements different cleanup
strategies for active VMs, deleted VMs, and expunged VMs.

- For active VMs: keep latest file, delete files older than 1 day
- For deleted VMs: keep latest for 90 days, others for 7 days
- For expunged VMs: delete all records immediately
- For backup files: keep based on resource type and age
- Send KVM delete commands before removing DB records
- Handle host deletion scenarios properly

Related: ZSV-11310

Change-Id: I7a78676c6775746d637762716367716c68617a74

Author: Zhang Wenhao