[2.0] New `queue` implementation

[hmans]

eg.

queue(() => world.remove(entity))

/* Later */
queue.flush()

[hmans]

I've decided that Miniplex 2.0 will not ship with any queueing mechanism built-in, and will be recommending users to model queuing concerns using the ECS itself, or use out-of-band solutions (like my tiny @hmans/queue package, but there are probably also many others.)