NSFS | NC | Let the User Explicitly Set `allow_bucket_creation`

[shirady]

Environment info

• NooBaa Version: master
• Platform: NC

Actual behavior

1. Currently, the allow_bucket_creation value is inferred from the new_buckets_path: if the user passes a value to new_buckets_path then it is true, otherwise false.

Expected behavior

1. Allow the user to pass the value of allow_bucket_creation explicitly and update it (from true to false and vice versa).

Steps to reproduce

1. none

More information - Screenshots / Logs / Other output

Please take into account that it will be a flag is manage nsfs CLI and a property inside the file when using the from-file option.

[shirady]

Please add a unit test for updating a bucket (see this comment with manual description):

1. Create an account with new_buckets_path (allow_bucket_creation is true).
2. Created a bucket.
3. Update the account (in a way you choose) so allow_bucket_creation will be false.
4. Update the bucket already created (step 2) - for example --fs_backend GPFS instead of the default value => should pass.

[shirady]

The verification will be tracked by the BZ 2262992.

[shirady]

It was validated in mentioned BZ above.