Deprecate the "Master" nomenclature

[tlfeng]

Is your feature request related to a problem? Please describe.
OpenSearch repository is going to replace the terminology "master"with "cluster manager".
issue: opensearch-project/OpenSearch#472, with the plan for its terminology replacement.

Although the existing usages with "master" will be supported in OpenSearch version 2.x until further notice to keep the backwards compatibility, please prepare for the nomenclature change in advance, and replace all the usages with "master" terminology in the code base.

Describe the solution you'd like
Replace the terminology "master" with "cluster manager".

When being compatible with OpenSearch 2.0:

• Replace "master" in code comment and internal variable name.
• Deprecate REST API (request parameter) that contains "master" and provide alternative inclusive usage:
  deprecate parameter "master_timeout" and add new parameter "cluster_manager_timeout" in RestExplainAction (updated after the below comment)

When being compatible with OpenSearch 3.0:

• Replace "master" in the reference to OpenSearch Java API
  (most of the new APIs are available in version 2.2, except AcknowledgedResponse)
  • clusterStateRequest.masterNodeTimeout() -> clusterManagerNodeTimeout()
  • import org.opensearch.action.support.master.MasterNodeRequest -> import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest
  • import org.opensearch.action.support.master.TransportMasterNodeAction -> import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction
  • import org.opensearch.action.support.master.AcknowledgedResponse -> import org.opensearch.action.support.clustermanager.AcknowledgedResponse (will be available in version 3.0)

Describe alternatives you've considered
None.

Additional context

Related issues:

• [FEATURE] Change the "master" nomenclature documentation-website#450 Describes the newly added alternative OpenSearch REST API / Setting for all the non-inclusive usages.
• Replace "master" terminology in Java APIs OpenSearch#1684

Note about the API request parameter master_timeout:
From my understanding, the parameter master_timeout is used in "Explain Index" API of the plugin, and it's independent with OpenSearch (core), so you could deal with it alone.
I suggest to deprecate the request parameter master_timeout, and add a new request parameter cluster_manager_timeout. Then remove the support of parameter master_timeout in the future.

How OpenSearch deal with the API request parameter master_timeout:
In OpenSearch, the parameter master_timeout is deprecated and will be replaced by parameter cluster_manager_timeout.
The code change was tracked in the issue opensearch-project/OpenSearch#2511

The timeline for deprecating the parameter master_timeout is special in OpenSearch (core):

1. In version 2.0: new parameter cluster_manager_timeout is added, while no warning for using master_timeout.
2. In version 3.0: deprecation warning will be emitted if using the parameter master_timeout.
3. In version 4.0: the support of master_timeout will be removed.

Technically it is fine to keep using the parameter master_timeout when being compatible with OpenSearch 2.0, but deprecation warning will be shown in 3.0 .

[dblock]

For 2.0, at a minimum please ensure that the plugin is not calling any deprecated APIs in core or another plugin, and confirm below, then remove the 2.0.0 label. If you have time, do the complete deprecation as described in this issue.

[CEHENKLE]

@opensearch-project/index-management Can you please verify @dblock's question so we can remove the 2.0 label? Thanks

[bowenlan-amzn]

@tlfeng helps pointing out the master_timeout API parameter usage in our repo.
e.g.

index-management/src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/resthandler/RestExplainAction.kt

Line 80 in 2d3fd97

request.paramAsTime("master_timeout", MasterNodeRequest.DEFAULT_MASTER_NODE_TIMEOUT),

And the related issue: opensearch-project/OpenSearch#2928
We will follow the same method as in the above issue to deal with this parameter

[anasalkouz]

Java APIs completed and released on 2.2 except for AcknowledgedResponse.
@bowenlan-amzn Could you please complete the remaining part from your end? let's target 2.3 for all usages except for AcknowledgedResponse (there will be separate issue to track it).