Move sortField to relationship setup (#4304)

* Add migration

* Add sort field to relation types

* Remove sortfield options in favor of relationship

* Add sort field configuration to relational setup

* Save m2a sortfield on the correct row

* Add default sort field to system data

api/src/database/system-data/relations/relations.yaml

@@ -8,6 +8,7 @@ defaults:
   one_field: null
   one_primary: null
   junction_field: null
+  sort_field: null
 
 data:
   - many_collection: directus_users