storage: handle errors in batch objects delete action

[kobajagi]

Description

Batch objects delete API method from aws-sdk-go-v2 will not return error as second argument if individual objects failed to be deleted. Instead it will return both list of deleted objects and list of errors in result structure.

This prints errors (if any) after the list of successfully deleted files.

Checklist

(For exoscale contributors)

• [ ] Changelog updated (under Unreleased block)
• [ ] Testing

Testing