HDDS-7994. Expose information via the ClusterState endpoint on keys and Directories marked for deletion

[ArafatKhan2198]

What changes were proposed in this pull request?

• When a key is deleted, it is not immediately removed from the metadata but marked for deletion and moved to the DeletedTable. The KeyDeletingService sends requests to delete the corresponding data blocks associated with the keys. Once Recon detects the deletion, it updates its metadata store to reflect the change and retains a record of the deleted key in the DeletedTable for administrators to query.
• This information can be useful for auditing, compliance, and troubleshooting purposes. Hence in short the main purpose is to get a quick idea of the deletion progress.
• This information will be displayed on the overview page of recon which gets populated with the information provided by the ClusterStateEndpoint
• The Jira is coming out of the following discussion :- HDDS-7926. [hsync] Recon throws ClassCastException. #4266 (comment)

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-7994

How was this patch tested?

Unit Testing

[ArafatKhan2198]

@jojochuang @ChenSammi @devmadhuu @dombizita can you please take a look!

[kerneltime]

@sumitagrawl can you please take a look?

[sumitagrawl]

@ArafatKhan2198 Count of deleted keys is one of sub-part of features which is under analysis phase, as part of that, it need expose Recon Insight for deletedTable, deletedDirectoryTable, and other metadata, to show data in progress of deletion. So there can be changes in interface and details to be exposed.

I think we can hold this till that is designed. @devmadhuu is working over this.

[sumitagrawl]

@ArafatKhan2198 LGTM, plz add testcase for deletedDir Count also

[sumitagrawl]

@ArafatKhan2198 Thanks for working, LGTM +1

[jojochuang]

+1 Merging it

[jojochuang]

Merged. Thanks @sumitagrawl for the review!