HDDS-9738. Display pipeline and container counts for the decommissioning Datanode

[Tejaskriya]

What changes were proposed in this pull request?

In order to track the progress of the decommissioning of a datanode, the number of pipelines associated to the datanode and the number of containers on the datanode blocking the decommissioning (i.e., unhealthy and under-replicated containers) is necessary to be shown as a part of the decommission status command.
These counts, along with the time at which decommission was started for the datanode are stored as a part of metrics in NodeDecommissionMetrics. In this PR, the JMX endpoint for SCM is queried for the NodeDecommissionMetrics class and the response is parsed to display the counts and starttime for each node currently in DECOMMISSIONING.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-9738

How was this patch tested?

Tested locally in docker set-up:

$ ozone admin datanode status decommission

Decommission Status: DECOMMISSIONING - 2 node(s)

Datanode: e56afcce-f5b5-4980-8b1b-d55a5714ad3c (/default-rack/172.21.0.9/ozone-datanode-4.ozone_default)
Decommission started at : 170558246119118/01/2024 12:54:21 UTC
No. of Pipelines: 1
No. of UnderReplicated containers: 0
No. of Unclosed Containers: 0

Datanode: 18e00b07-ad64-4b3f-a291-c786df35d6da (/default-rack/172.21.0.3/ozone-datanode-3.ozone_default)
Decommission started at : 170558244380918/01/2024 12:54:03 UTC
No. of Pipelines: 2
No. of UnderReplicated containers: 0
No. of Unclosed Containers: 0

[Tejaskriya]

Abandoning this PR as I seemed to have created a mess during rebasing the patch!
I have raised another PR: #6083 for the same changes