[FEATURE] Change the "blacklist / whitelist" nomenclature

[tlfeng]

Is your feature request related to a problem?
OpenSearch repository is going to replace the terminology "blacklist / whitelist" with "denylist / allowlist".
issue: opensearch-project/OpenSearch#1483, with the plan for its terminology replacement.

The existing OpenSearch REST APIs and settings will be deprecated in version 2.0, and eventually be removed in at least version 3.0. Please prepare for the nomenclature change in advance.

What solution would you like?
Replace the terminology "blacklist / whitelist" with "denylist / allowlist"

1. Inform the user about the nomenclature change in advance in the documentation.
2. Replace all the internal usages with "master" word in the code base.

The impact to the users is concentrated in a setting name change reindex.remote.whitelist. The issue opensearch-project/OpenSearch#1547 shows all the detailed code change.

Users are still able to use the setting reindex.remote.whitelist, but it will result a deprecation warning stored in log file.
It's suggested to use the new name reindex.remote.allowlist.

Expected behavior of the setting:

• If the new setting is configured, value of the old setting will be ignored.
• If the new setting is not configured, value of the old setting will be valid.

What alternatives have you considered?
none.

Do you have any additional context?
none.