Batch queuing function in Laravel-Excel

This contribution adds support for Laravel Job Batching (Laravel 8+) to queued imports and exports, enabling multiple jobs to be grouped into a single batch and managed as a unified operation.

Context

Laravel Excel already supported:

• Chunked (batched) data processing
• Queue-based execution via ShouldQueue

However, it lacked support for:

• Grouping generated jobs into a Laravel batch
• Tracking overall progress
• Executing lifecycle callbacks
• Managing or cancelling the operation as a single unit

What Was Implemented

This change integrates Laravel Job Batching, allowing:

• All jobs generated by an import/export to be grouped
• Execution via Bus::batch()
• Centralized control and observability over the entire process