Add ability to change the resources for the workers once the cluster is running

[npatel-cars]

Problem:
Currently, we can't increase or decrease the amount of resources the worker has while the cluster is running. If you want to change the size, the whole cluster needs to be destroyed and restarted. It would be helpful to be able to change the worker fleet size without restarting the cluster.

Goal:
Add the ability to change the amount of resources for the worker fleet.
Add the ability to destroy the worker fleet but leave the master fleet.