* Added a junction table for custom properties to improve data normalization
* Modified the `insert_item_by_url` function to handle custom properties through the junction table
* Introduced `get_url_id` and `get_or_create_property` helper functions for improved code organization
* Updated the `insert_item_by_url` function to use the new helper functions and handle custom properties correctly
* Improved error handling and logging throughout the database module