Feature Request: No ingest functionality to put multiple records of a data frame in feature group.

In new SDK there is no `ingest` method to import a whole dataframe in a go creating difficulties in importing multiple records simultaneously.

Previous SDK had below code to inject a dataframe:

`customers_feature_group.ingest(data_frame=customer_data, max_workers=3, wait=True)`

sagemaker_core does not have this method/functionality. Without this, it will be difficult to import all records in feature store.

Old [sagemaker SDK document](https://sagemaker.readthedocs.io/en/stable/amazon_sagemaker_featurestore.html) containing ingest method.

If this functionality is not present in new SDK then how to mitigate this?

Review the new SDK's feature-group API in sagemaker-core and compare it with the previous SDK documentation linked in the issue. Determine how dataframe ingestion, max_workers, and wait are expected to work, and document or implement the agreed path for importing multiple records into a feature group.

Written by the indexing model from the issue text.