Add method to bulk delete blobs from S3Storage

Description

Currently, we do not have a way to bulk delete blobs from S3 Storage. This MR adds this method.

We might want more intelligent error handling, since we don't propagate any info on which files were deleted, and which files failed to delete.

To Do:

• Implement function call
• Implement error handling
• Add tests

Issue:

#270 (closed)