Adds duplicates configuration

assets/admin.pack.js

assets/js/admin/source-priority.js

config/services.yaml

package.json

src/Admin/ConfigurationDuplicatesAdmin.php

src/Controller/DuplicatesController.php

src/Document/Configuration.php

src/Document/Configuration/ConfigurationDuplicates.php

...admin/core_custom/custom-fields/source-priority.html.twig

templates/admin/edit/edit_configuration.html.twig

templates/admin/edit/edit_configuration_duplicates.html.twig

templates/admin/pages/bulks/bulk_index.html.twig

yarn.lock