[feature] Add support for FIND_IN_SET operator

[SamuelPietro]

Description

This PR adds support for the FIND_IN_SET operator in the Medoo database framework. The implementation ensures compatibility with array values and updates parameter mapping to handle multiple values correctly.

Changes

• Implemented FIND_IN_SET operator in the dataImplode method.
• Added logic to handle array values for the FIND_IN_SET operator.
• Updated parameter mapping to ensure unique keys for each value.

Impact

This enhancement allows users to use the FIND_IN_SET operator in their queries, providing more flexibility in handling comma-separated values within the database.

Testing

• Added unit test to verify the functionality of the FIND_IN_SET operator.
• Tested with various scenarios to ensure correct behavior and compatibility.

[catfan]

Thank you for your contribution.

The FIND_IN_SET is only available for MySQL and MariaDB. It's not a general function.

I may design a new operator to support every database function call and can support this case also.