Implement Post-Processor Hooks for Refreshing Index after Ingestion

Is your feature request related to a problem? Please describe.
Currently our ETL job runs every 30 minutes and inserts a file into S3, triggering OpenSearch ingestion pipeline. Due to varying ETL completion time, it's challenging to determine suitable refresh_interval at the index level that works consistently for all scenarios.

As a result of this behavior - there is a delay in the data being available even though the ingestion to OpenSearch is complete.

Describe the solution you'd like
We propose to add a new configuration option for http post-processor hooks in the Data Prepper pipeline definition, which will allow us to specify the http POST endpoint and make refresh API call( /index-name/_refresh), post pipeline ingestion is completed.

Currently the processor available in the pipeline definition only works before ingesting data to OpenSearch.

Describe alternatives you've considered (Optional)
Provide refresh option at pipeline index settings which will internally refresh the index after the execution of pipeline.

Additional context
N/A

Start by reviewing the existing pipeline processor configuration that runs before OpenSearch ingestion and the post-ingestion pipeline lifecycle. Define the HTTP POST hook configuration and its execution point, with completion shown by a refresh request being sent after ingestion finishes; the issue does not name specific files or tests.