world_actor -> orchestrator
add 'chunk' actor (WIP) to manage chunks of the game world in a
distributed way

the chunk actor, with this setup, will manage the entire lifecycle of
its bit of the game world.

except for persisting the state after a tick.
this will be handled by a singular process (orchestrator) to avoid
inconsistencies if/when some chunks fail to persist their state

when moving units (or structures) the user code will have to consult the
chunk actor that the unit is currently in.
i.e. the response times need to be low to not impede the users ability
to make choices when moving many units (large scale battle for example)

other actions (attack, heal, harvest) should be possible without needing
a central source of truth

if a user schedules multiple actions which conflict, for example:
a single unit attacking multiple targets, only the first one should
actually get executed

if a unit attacks and moves the attack should be 'run' using the
pre-move world state

i.e. you can move and attack in the same tick
this also means if a unit is within attack reach, an attack on it will
always hit. even if they decide to move out of range again.