[FLINK-38447] Add table sink support for Elasticsearch 8 connector

[lwn3148]

Currently, the Elasticsearch 8 connector lacks a Table API sink implementation. This contribution adds a Table sink to the connector. To maintain configuration consistency with existing Elasticsearch connectors (e.g., ES 6/7), some utility classes and configuration definitions were directly reused from the base module, but the configuration options are adapted to the capabilities of the Elasticsearch8AsyncSink.

Key configuration changes include:

Removed options not supported by Elasticsearch8AsyncSink:

• sink.bulk-flush.backoff.strategy
• sink.bulk-flush.backoff.max-retries
• sink.bulk-flush.backoff.delay

Added new options:

• sink.bulk-flush.max-buffered-actions
• ssl.certificate-fingerprint

Retained and aligned all other options with the Elasticsearch8AsyncSink configuration.

[boring-cyborg]

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