NSFS | Versioning | List Object Version - Support for Null Version

[shirady]

Explain the changes

1. NSFS versioning list-object-versions operation - add support for null version id (details about the gap).
   Before this change when we had a version id of null the behavior was not expected, when I test it I saw:
   
2. Change the method _get_version_id_by_stat to function outside of the NameSpaceFS class.
    

Issues: Gaps

1. GPFS was not tested yet with these changes.
    

Testing Instructions:

Manual Tests:

1. Change the configuration of NSFS Versioning to be Enabled in file config.js and change config.NSFS_VERSIONING_ENABLED to true.
2. Deploy noobaa system on minikube (Based on the instructions here - the steps of ‘Build images’ and ‘Deploy noobaa’).
   Note: nb is an alias that runs the local operator from build/_output/bin (alias created by devenv).
3. Deploy NSFS on minikube (Based on the instructions here).
4. Use AWS CLI and use the put-object command (here is a link to their doc).
5. Set the bucket to versioning Enabled and put-object of another key (here is a link to their doc).
6. Set versioning to suspended and put versions of the same object that were uploaded before (steps 4 and 5).
7. Use AWS CLI and use the list-object-versions command (here is a link to their doc).
    
   While you add objects to the bucket you can view the changes
8. Connect to the endpoint pod: kubectl exec -it [endpont-pod-name] -- bash.
9. Move to the bucket path (if you did it as written in the wiki it would be cd /nsfs/fs1/bucket-path/).
10. Use Linux commands to list the files (including hidden files), for example: ls -al.
     

Test stat error edge case (and no old_version edge case):

Status: When we have .versions directory and inside it only 1 null version, add an error after stat. Should list object version without null version.

Run Unit Tests:

1. In file src/test/unit_tests/sudo_index.js leave only require('./test_bucketspace_versioning'); (rest of test files  comment out).
2. From the core tab in the terminal run: make root-perm-test (You should see "144 passing" at the end of the output).
    

• Tests added: NSFS list object version for null version cases only (using prefix to decrease the list and focus on the null version tests).

[vh05]

/lgtm

I feel one more approval would be better