[core] Support spill objects to node_id sub-directory

[ruisearch42]

Why are these changes needed?

When system-config was used to specify the spilling location, only one direction can be used which is the same for all the workers. When the dir is a shared NFS, conflict might happen.

https://docs.ray.io/en/latest/ray-core/objects/object-spilling.html#cluster-mode

ray start --head --system-config='{"object_spilling_config":"{\"type\":\"filesystem\",\"params\":{\"directory_path\":\"/tmp/spill\"}}"}'

This PR adds support for using <NODE_ID> as part of the spilling directory name to avoid the conflicts. Specifically,
the spilling directory would be set to /tmp/spill/ray_spilled_objects_<NODE_ID>. Note that this change is not backwards compatible since it changes the spill directory name. We preferred this as opposed to introducing an additional config argument (API change) that controls whether to use <NODE_ID> as part of the directory name.

Note that after this change Ray doesn't clean up spill directory at start-up (as it has no information of the old node id), and leaves it to external system such as VM clean-up. As future work, functionality should be added to clean up spill directory at node shutdown time.

Related issue number

Closes #44206
Fixes postmerge errors in #44341

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