Change the "Blacklist / Whitelist" nomenclature

[tlfeng]

Is your feature request related to a problem? Please describe.
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.

Although the existing usages with "blacklist / whitelist" will be supported in OpenSearch version 2.x until further notice to keep the backwards compatibility, it's suggested to prepare for the nomenclature change in advance, and replace all the usages with "blacklist / whitelist" terminology in the code base.

Describe the solution you'd like
Replace the terminology "blacklist / whitelist" with "denylist / allowlist".

When being compatible with OpenSearch 2.0:

• Replace "blacklist / whitelist" in code comment

Describe alternatives you've considered
None.

Additional context