[FEA]: nemo_retriever library: make async ingestor API with ability to check job status

[randerzander]

Is this a new feature, an improvement, or a change to existing functionality?

Improvement

How would you describe the priority of this feature request

Significant improvement

Please provide a clear description of problem this feature solves

Should following the existing nv_ingest async API design, but adapted for the nemo_retriever Python API

Describe the feature, and optionally a solution or implementation and any alternatives

ability to submit ingestion jobs that run in the background without blocking the main thread

It should return job/task IDs which the user can use to check status of individual documents

Additional context

No response

[randerzander]

Need the following:
 • ingest_async() returning a future with return_traces and return_failures functionality
 • get_status() - per-document/filepath status map
 • completed_jobs(), failed_jobs(), remaining_jobs() counters