feat: export presence

[adrienaury]

Add a new option for export option in table.yaml.

Context

The current export parameter allows configuring different behaviors for exporting data in JSON. A new feature is requested to add a specific behavior that only indicates the presence of a value in the database.

Objective

Create a new presence option for the export parameter with the following behavior:

• If the database value is null, the JSON output will be "null".
• If the database value is not null (regardless of the content), the JSON output will be "true".

Usage Examples

// With export: "presence"
{ "field": null } // if the database value is null
{ "field": true } // if the database value is not null

Implementation

Add presence as an available option for the export parameter.
Implement conditional logic to handle null and true in the JSON output depending on the database value presence.

Testing

• Test the behavior for cases where the database value is null.
• Test the behavior for cases where the database value is not null.
• Ensure compatibility of this new option with existing behaviors of the export parameter.