Add more index options for streaming job

[dai-chen]

Description

1. Add watermark_delay option for MV
2. Add generic extra_options for other source and sink options
3. Refactor MV UT with Spark comparePlans() util methods

Documentation

Please see doc here for more details: https://github.com/dai-chen/opensearch-spark/blob/add-more-index-options-for-streaming/docs/index.md#create-index-options

Example

CREATE MATERIALIZED VIEW http_logs_metrics_all
AS
SELECT
  window.start AS startTime,
  COUNT(*) AS count
FROM ds_tables.http_logs
GROUP BY TUMBLE(`@timestamp`, '1 Hour')
WITH (
  auto_refresh = true,
  checkpoint_location = "s3://test/checkpoints/",
  watermark_delay = '1 Minute',
  extra_options = '{"myglue.ds_tables.http_logs": {"maxFilesPerTrigger": "1"}}'
);

Issues Resolved

#25

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