feat: implement takeover for nydusd fusedev daemon

This patch implements the `save` and `restore` functions in the `fusedev_upgrade` in the service create.
To do this,
- This patch add a new create named `nydus-upgrade` into the workspace. The `nydus-upgrade` create has some util functions help to do serialization and deserialization for the rust structs using the versionize and snapshot crates. The crate also has a trait named `StorageBackend` which can be used to store and restore fuse session fds and state data for the upgrade action, and there's also an implementation named `UdsStorageBackend` which uses unix domain socket to do this.
- as we have to use the same fuse session connection, backend file system mount commands, Vfs to re-mount the rafs for the new daemon (created for "hot upgrade" or failover), this patch add a new struct named `FusedevState` to hold these information. The `FusedevState` is serialized and stored into the `UdsStorageBackend` (which happens in the `save` function in the `fusedev_upgrade` module) before the new daemon is created, and the `FusedevState` is deserialized and restored from the `UdsStorageBackend` (which happens in the `restore` function in the `fusedev_upgrade` module) when the new daemon is triggered by `takeover`.

Signed-off-by: Nan Li <[email protected]>