The challenge complification

Updated the challenges.yml to follow a format from "old-days".

_Features_

• Challenges can now have an offset value, allowing for more detailed layout of challenges
  • An offset of -1 will mean, it will take over the previous spot, once it has been completed
• Permission nodes obtained from completing challenges is shared with members on the island, when challengeSharing: island
• Permission nodes are lost when leaving the island