Improve get_players retrieval in world state

[github-actions]

this is going to be not-at-all performant in the long run, and we'll need a way to

cache this or index it better

moor/crates/db/src/odb/rb_worldstate.rs

Line 112 in 47435a1

// TODO: Improve get_players retrieval in world state

    }

    fn get_players(&self) -> Result<ObjSet, WorldStateError> {
        // TODO: Improve get_players retrieval in world state
        //   this is going to be not-at-all performant in the long run, and we'll need a way to
        //   cache this or index it better
        get_all_object_keys_matching(