HDDS-6819. Add LEGACY to AllowedBucketLayouts in CreateBucketHandler

[tanvipenumudy]

What changes were proposed in this pull request?

This task is to add LEGACY to AllowedBucketLayouts in the CreateBucketHandler class.

CreateBucketHandler.java#L65

enum AllowedBucketLayouts {
    FILE_SYSTEM_OPTIMIZED("FILE_SYSTEM_OPTIMIZED"),
    OBJECT_STORE("OBJECT_STORE"),
    LEGACY("LEGACY")

While executing the ozone sh bucket create command and passing an INVALID bucket layout, we currently get the following error message:

Invalid value for option '--layout': expected one of [FILE_SYSTEM_OPTIMIZED, OBJECT_STORE, DEFAULT, ] (case-sensitive) but was 'INVALID'

After the changes, this would be modified to:

Invalid value for option '--layout': expected one of [FILE_SYSTEM_OPTIMIZED, OBJECT_STORE, LEGACY] (case-sensitive) but was 'INVALID'

Similarly, ozone sh bucket create --help gives the following description for "-l", "--layout":

-l, --layout=<allowedBucketLayout>
                           Allowed Bucket Layouts: FILE_SYSTEM_OPTIMIZED,
                           OBJECT_STORE,

After the changes, this would be modified to:

-l, --layout=<allowedBucketLayout>
                           Allowed Bucket Layouts: FILE_SYSTEM_OPTIMIZED,
                           OBJECT_STORE, LEGACY

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-6819

How was this patch tested?

Added integration tests.

[rakeshadr]

+1 LGTM, thanks @tanvipenumudy for the contribution.

Thanks a lot @JyotinderSingh for the offline discussions to understand the ${COMPLETION-CANDIDATES} types.

[JyotinderSingh]

Thanks for the contribution @tanvipenumudy! The overall patch looks good to me, added a minor comment.

[JyotinderSingh]

Looks like the CI is having some issues right now, will retrigger these tests in a little bit.

[JyotinderSingh]

Thank you @tanvipenumudy for the patch, and @rakeshadr for the reviews and offline discussion. Merging this PR.