Use a command framework

[SirYwell]

LandLord has a fair amount of commands. That currently involves a lot of code that is just handling the command input. With a command framework, this part could be reduced. The remaining code concentrates on the actual execution and is easier to read and more maintainable.

There are several command frameworks already used in the minecraft community (acf, cloud). My personal preference is cloud, it allows defining commands using annotations or a builder similar to brigadier and has good brigadier/tab completion support. I'm not opposed looking into other alternatives, but I think reducing the command parsing overhead would be worth the work.