monofs

Implement tombstone for deletes.
Implement merging although it is a bit tricky.
- How do we handle "previous" field conflicts?
- Handling deletes with tombstones

monocore

Improve remove and copy performance.
- Sibling entries should be processed in parallel.
- Do the same for PermissionsGuard Drop implementation.
Fix copy and remove permission issues on Linux.
Use sqlitedb for maintaining running services state.
- Fix issue with services running even after the config is deleted.
- We should be able to guarantee that service is dead when the config is deleted.
Treating microvm management like a package manager.
- Store service rootfs, state, logs locally in a .mc directory kind of like ./node_modules.
- Store reference rootfses (oci & monofs) in home_dir with a special store that links to them from forked rootfses.
Support multiple registries.
- Use Reference type for image_ref where it makes sense: https://docs.rs/oci-spec/0.7.1/oci_spec/distribution/struct.Reference.html
- Qualify image names fully where needed. /:
- Instead of sanitizing image refs, we should just hash them instead.