Batching in NER pipeline
# 🚀 Feature request

Currently, the NER pipeline in transformers iterates through the list of input sentences and processes them, sequentially.
It would we beneficial to add batching support in the pipeline to decrease latency and use GPU more efficiently.

## Motivation

Batching will help use the GPU more efficiently and reduce latency by a lot. The NER pipeline is amazing with its post processing, could be a production ready construct if batching is added.

This issue has been discussed here - https://github.com/huggingface/transformers/issues/8942 at the end, but looks like no one is working on it actively.

## Your contribution

Working on this issue in this PR - https://github.com/huggingface/transformers/pull/11251

Please raise if this is on the radar already, will close the issue.

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.