Private, group, and global world instances

[TheBlackParade]

• Players should be able to have their own private game instance, including their own personal game objects, NPCs, and world items.
  • Players should not be able to see actions of other players in their private instance.
  • Other players should not be able to see the actions of this player in their private instance.
• Players should be able to join a group instance where they share the aforementioned resources - game objects, NPCs, and world items.
  • Players outside of this group instance should not be able to see the actions of those within.
  • Vise versa for those inside in instance.
• The game world should have a global instance that applies to all players and NPCs that are not assigned to a specific instance (they are not in private gameplay of any kind).
  • This is a game instance shared by everyone within the world that is not in a private instance.
  • All world items, objects, NPCsc, etc are visible to everyone inside the global instance.
• The global instance and private instances can not be engaged at the same time. The player must be either in the global instance or a specific instance - whether that be a group or private instance.
• Friends list status is independent of instances - a player is shown as online regardless of which instance type they are logged into.

[Tynarus]

Completed by #220