Ability to reset a quest and restart it

[BlackRam-oss]

Give the ability to reset a quest:

• [ ] Add a parameter: restart_label_name. That will be started when the Quest is restarted. This can be useful for changing values that have something to do with the Quest.
• [ ] Create a function in the Quest class that will set all values to 0 and start the Quest (if it is possible to reuse functions already present) and that eventually starts the previous label.
• [ ] Add a a button to reset the Quest
• [ ] Wiki
• [ ] Code-snippet