Allow variable DEFECT_DOJO_PRODUCT_TYPE_NAME empty

[tidusete]

Change default DEFECT_DOJO_PRODUCT_TYPE_NAME to allow empty values

Description

This MR modifies the default value of DEFECT_DOJO_PRODUCT_TYPE_NAME to allow empty strings as valid values. The change is motivated by the DefectDojo API's reimport-scan endpoint behavior, which only requires product_name and engagement_name for scan reimports, making the product_type_name parameter optional. This aligns our implementation with the API's capabilities and simplifies the configuration when using reimport functionality.

Technical Context

1. The DefectDojo API endpoint reimport-scan can operate with just:

   • product_name
   • engagement_name

2. Current Implementation Issue:

   • With the mandatory product_type_name configuration, if a product already exists in DefectDojo with the same name but under a different product_type, the API call fails due to a conflict
   • This forces users to ensure product_type alignment even when it's not necessary for the reimport operation
   • Making product_type_name optional avoids these conflicts and allows better integration with existing DefectDojo products

Changes

• Update README.md to document empty string as a valid option for DEFECT_DOJO_PRODUCT_TYPE_NAME
• Modify src/settings.py to set default DEFECT_DOJO_PRODUCT_TYPE_NAME to empty string

Documentation

Updated README.md to reflect the new default value and usage options, including explanation of API endpoint behavior and conflict resolution.