change object reward system in role, disable the possibility to create a new old object reward but it stay usable if existing in an import file / fix a bug in copied role save where he wasn't save

Task unity mode + fix on clear character in task reward on character delete + fix en translate of 'plan de relance'

fix bug on multiple creation of alternative tasks + snackbar alert on transform and delete alternative tasks

Changes to the tutorial + Removal of conditions on prerequisites (adding a condition on tasks other than subtasks preventing subtask prerequisites) + Addition of a condition for a unique common task symbol in a role + Fix clean-dialog text