Add basic party system

[exectails]

Add creating parties, teaming up with others, and everything else that goes into the basic party system.

https://treeofsavior.fandom.com/wiki/Category:Party

TODO: Write an outline for what's required of the party system.

[exectails]

Currently being worked on in a branch by @SalmanTKhan.

[felipecastagnarodecarvalho]

Working on it on #231 but I need help. A few things are wrong still...