Issue-3095515 applying kiamlaluno recommandations.

README.md

composer.json

src/Controller/AccessController.php

src/Plugin/ExternalDataSource/Countries.php

src/Plugin/ExternalDataSource/FranceRegions.php

src/Plugin/ExternalDataSource/FranceZipCodes.php

src/Plugin/ExternalDataSourceBase.php

...ugin/Field/FieldFormatter/ExternalDataSourceFormatter.php

src/Plugin/Field/FieldType/ExternalDataSource.php

...ield/FieldWidget/ExternalDataSourceAutoCompleteWidget.php

.../Field/FieldWidget/ExternalDataSourceCheckboxesWidget.php

...ugin/Field/FieldWidget/ExternalDataSourceSelectWidget.php