Add ingest API

[123vivekr]

Description

This API will push logs to stream based on header.

Separated out pushing log logic into push_logs() - avoid code redundancy

Expose /ingest API which push logs to a stream name based on header.
The header key is X-P-STREAM-NAME

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This PR has:

• been tested to ensure log ingestion and log query works.
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added documentation for new or modified features or behaviors.

[nitisht]

Thanks for the PR @123vivekr we'll take a look

[trueleo]

Thank you for the PR