NC | Bucket Owner Removal

[romayalon]

Disclaimers -

1. This PR is based on the bucket owner removal part of Nc account by id #8167 written by @alphaprinz.
2. This PR is dependent on merging - NC | Config Dir Restructure #8279 and currently, cherry-picking its only commit, which will be removed after its merge.

Explain the changes

1. Schema - Removal of bucket_owner property requirement from nsfs_bucket_schema.js. Didn't remove it completely from the schema for backward compatibility.
2. CLI - Create/Update flows - removal of bucket_owner property usage from the schema, but left it on the CLI API which means that on create/update bucket --owner flag is still the name of the account, and it'll be mapped to an id internally - owner_account.
3. S3 API (BucketspaceFS) -

• read_bucket_sdk_info() - since we don't keep the bucket owner name we now read the account config file by its id (owner account) and set the bucket_owner run time object.
• create_bucket() - removed bucket_owner from new_bucket_defaults.

4. IAM API (AccountspaceFS) -

• _check_if_root_account_does_not_have_buckets_before_deletion() - Updated usage by id instead of by name.

6. Tests/Docs - Removed and updated bucket_owner related changes.

Issues: Fixed #xxx / Gap #xxx

1. Fixed #Account update with account name is not updating bucket_name.json file automatically #8080
2. Gap - we need to remove the following line when having IAM users in users/ directory (this will mean that a root account can have the same name as an IAM user) @shirady

-   if (account_identifier === bucket_owner.unwrap()) return true;
+   if (owner_account && account._id === owner_account.id) return true;
+   //name check - only for root accounts
+   if (!account.owner && account_identifier_name === bucket_owner.unwrap()) return true;

Testing Instructions:

• Doc added/updated
• Tests added

[shirady]

@romayalon could you please update the the PR description (and attach the issue)?

[shirady]

LGTM