feature: The ability to create instances of maps for personal use, guild use, and party use.

[AlexVild]

Is your feature request related to a problem? Please describe.
It can be very challenging to design certain gameplay elements without the ability to create an instance of a map and only give it to a subset of players.

Describe the solution you'd like
I would like to see instancing introduced, with the ability to warp players to:

• Personal instances, that are just for them
• Guild instances, in which all guild members can warp to the same instance, if they're in the same guild
• Shared instances, in which members of a party could warp to a shared instance.