FHIR Batch Delete Based on a List of Resource IDs in Google Cloud Healthcare API

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**The issue you're having must be related to a file in this repository.** We are unable to provide assistance for issues unrelated to samples in this repository.

Please include as much information as possible:

## Is your feature request related to a problem? Please describe.

I'm working on a project using the Healthcare API FHIR Storage and I'm frustrated by the difficulty of deleting all resources for a customer. The current samples include a delete_resource() function, but due to data integrity constraints in FHIR Storage, I cannot directly delete a resource if it is referenced by another resource.

## Describe the solution you'd like.

I created a function called batch_delete() that receives a list of resource IDs to be deleted in a single transactional call to the Healthcare API. This function will delete all specified resources at once, ensuring transactional integrity in the FHIR Storage.

## Describe alternatives you've considered.

I have tried using the delete_resource() function from [this sample](https://github.com/GoogleCloudPlatform/python-docs-samples/blob/main/healthcare/api-client/v1beta1/fhir/fhir_resources.py), but I encountered issues due to integrity constraints.

## Additional context.

My idea is to contribute to this repository by creating the batch_delete() function. Additionally, I could develop a batch_deletion_by_patient_id() function, which would be highly beneficial.

Thanks!