Searching for conflicts requires a field 'slug' in the entity

[cammanderson]

I know it is implied (e.g. get/set slug), but you may want to implement a naming convention around slugs, such as meta_slug or similar. Is it possible to refactor somehow so that entities can declare what the field is to search on? Thinking like how the security package configures the username field (e.g. in security with the entity section).

Currently the Listener uses the repository to search for conflicts based on the slug field.