Add option to exclude families from import

[claudio-ferraro]

This PR introduces a new feature to exclude families from being imported from Akeneo. This is useful for scenarios where certain families should not be synchronized to Magento.

Key changes:

• Added a new configuration field "Families to Exclude" in the "Filter Products" section of the Akeneo Connector configuration.
• Implemented logic to filter out products belonging to the excluded families during the import process.
• Updated the README to document the new feature.

Import Logic Explanation:

• "Families to exclude" is empty: Only the families selected in "Families to import" will be imported.
• "Families to import" is empty: All families will be imported, except those selected in "Families to exclude".
• Both selections are empty: All families will be imported.

[rbnmulder]

You can convert this to an after Plugin. Check if array is empty and if there are families to exclude then fetch all families to filter.

[rbnmulder]

You can convert this to an after Plugin. Check if array is empty and if there are families to exclude then fetch all families to filter.