partition reassignment logic - enhancement

[everyusernameisalreadytaken]

I would like to be able to spread partition leaderships among brokers in a nice round robin way without having to do every partition of every topic separately. When I have hundreds of topics and 50+ partitions per topic, kafkactl alter partition my-topic 3 -r 1,3,5 becomes unworkable. I'd rather have something like kafkactl alter topic my-topic --assign-broker <roundrobin|random|etc>

Alternatively, or in addition, it would be nice to be able to feed kafkactl partition reassignment json or yaml or csv file.