Improvements to Bulk Upload and usage instructions

Description

1. Usage instructions for the developers for implementing bulk upload.
2. Workflow changes to reduce database accesses.

Type of PR This PR is an improvement.

Technicalities

• The instructions are in the following file app/cake/src/Controller/Component/BulkUploadComponent_instructions.md

Tests

• Test for publications bulk upload using the file: publication_bulk_import01_-_Sheet1.csv
• Check the component usage instructions.