This commit improves the hypervisor by:
- Adding support for detecting base image formats using `qemu-img info`.
- Dynamically setting the base image format for overlay creation.
- Automatically converting non-raw images to raw format for bhyve compatibility.
- Updating `Cargo.toml` to include `serde_json` for JSON parsing.
- Modifying default working directory logic for `ZonesHypervisor`.
This commit replaces the `libvirt` crate with the `virt` crate for managing the libvirt backend on Linux. Key changes include:
- Updated `Cargo.toml` dependencies and feature configuration.
- Refactored hypervisor implementation to align with `virt` crate API.
- Improved error handling and lifecycle management for VMs and networks.